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  pdftitle={SDCC Compiler User Guide},
  pdfauthor={SDCC development team},
  pdfsubject={installation, user manual},
  pdfkeywords={68hc08 8032 8051 ansi c compiler assembler CPU DS390 embedded development free Floating Point Arithmetic Freescale GPL HC08 inline Intel ISO/IEC 9899:1990 Linux MAC OS X manual Maxim mcs51 Microchip microcontroller open source PIC Unix Windows Z80 Zilog},
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\begin_body

\begin_layout Standard
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Please note: double dashed longoptions (e.g.
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\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
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-
\end_layout

\begin_layout Standard
Two resp.
 three consecutive dashes would otherwise result in a long resp.
 extra long dash.
\end_layout

\begin_layout Standard
Architecture specific stuff (like memory models, code examples) should maybe
 later go
\end_layout

\begin_layout Standard
into seperate sections/chapters/appendices (it is hard to document PIC or
 Z80 in 
\end_layout

\begin_layout Standard
a 8051 centered document) - for now simply add.
\end_layout

\end_inset


\end_layout

\begin_layout Title
SDCC Compiler User Guide
\end_layout

\begin_layout Date

\size normal
SDCC 2.8.1
\size footnotesize

\newline
$Date:: 2008-05-01#$ 
\newline
$Revision: 5151 $
\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
The above strings enclosed in $ are automatically updated by Subversion
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\end_inset


\end_layout

\begin_layout Standard
\begin_inset LatexCommand \tableofcontents{}

\end_inset


\end_layout

\begin_layout Chapter
Introduction
\end_layout

\begin_layout Section
About SDCC
\end_layout

\begin_layout Standard

\series bold
SDCC
\series default
 (
\emph on
S
\emph default
mall 
\emph on
D
\emph default
evice 
\emph on
C
\emph default
 
\emph on
C
\emph default
ompiler) is free open source, retargettable, optimizing ANSI-C compiler
 by 
\series bold
Sandeep Dutta
\series default
 designed for 8 bit Microprocessors.
 The current version targets Intel MCS51 based Microprocessors (8031, 8032,
 8051, 8052
\begin_inset LatexCommand \index{8031, 8032, 8051, 8052, mcs51 CPU}

\end_inset

, etc.), Dallas DS80C390 variants, Freescale (formerly Motorola) HC08 and
 Zilog Z80 based MCUs.
 It can be retargeted for other microprocessors, support for Microchip PIC,
 Atmel AVR is under development.
 The entire source code for the compiler is distributed under GPL.
 SDCC uses ASXXXX
\begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}

\end_inset

 & ASLINK
\begin_inset LatexCommand \index{aslink}

\end_inset

, an open source retargetable assembler & linker.
 SDCC has extensive language extensions suitable for utilizing various microcont
rollers and underlying hardware effectively.
 
\newline

\newline
In addition to the MCU specific optimizations SDCC also does a host of
 standard optimizations like:
\end_layout

\begin_layout Itemize
global sub expression elimination, 
\end_layout

\begin_layout Itemize
loop optimizations (loop invariant, strength reduction of induction variables
 and loop reversing), 
\end_layout

\begin_layout Itemize
constant folding & propagation, 
\end_layout

\begin_layout Itemize
copy propagation, 
\end_layout

\begin_layout Itemize
dead code elimination 
\end_layout

\begin_layout Itemize
jump tables for 
\emph on
switch
\emph default
 statements.
\end_layout

\begin_layout Standard
For the back-end SDCC uses a global register allocation scheme which should
 be well suited for other 8 bit MCUs.
 
\newline

\newline
The peep hole optimizer uses a rule based substitution mechanism which
 is MCU independent.
 
\newline

\newline
Supported data-types are:
\end_layout

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width
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default
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bool
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1 bit
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unsigned
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char
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8 bits, 1 byte
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short
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16 bits, 2 bytes
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int
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16 bits, 2 bytes
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long
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32 bits, 4 bytes
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signed
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float
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4 bytes IEEE 754
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signed
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1.175494351E-38, 
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3.402823466E+38
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pointer
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1, 2, 3 or 4 bytes
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generic
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</lyxtabular>

\end_inset


\newline
The compiler also allows 
\emph on
inline assembler code
\emph default
 to be embedded anywhere in a function.
 In addition, routines developed in assembly can also be called.
\newline

\newline
SDCC also
 provides an option (-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-cyclomatic) to report the relative complexity of a function.
 These functions can then be further optimized, or hand coded in assembly
 if needed.
 
\newline

\newline
SDCC also comes with a companion source level debugger SDCDB.
 The debugger currently uses ucSim, a free open source simulator for 8051
 and other micro-controllers.
\newline

\newline
The latest SDCC version can be downloaded from
 
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}

\end_inset

.

\series bold
 
\series default
\emph on
Please note: the compiler will probably always be some steps ahead of this
 documentation
\series bold
\emph default

\begin_inset LatexCommand \index{Status of documentation}

\end_inset


\begin_inset Foot
status open

\begin_layout Standard
Obviously this has pros and cons
\end_layout

\end_inset

.
\end_layout

\begin_layout Section
Open Source
\end_layout

\begin_layout Standard
All packages used in this compiler system are 
\emph on
open source
\emph default
 and 
\emph on
freeware
\emph default
; source code for all the sub-packages (pre-processor, assemblers, linkers
 etc.) is distributed with the package.
 This documentation is maintained using a free open source word processor
 (LyX).
\newline
This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License
\begin_inset LatexCommand \index{GNU General Public License, GPL}

\end_inset

 as published by the Free Software Foundation; either version 2, or (at
 your option) any later version.
 This program is distributed in the hope that it will be useful, but WITHOUT
 ANY WARRANTY; without even the implied warranty
\begin_inset LatexCommand \index{warranty}

\end_inset

 of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 See the GNU General Public License for more details.
 You should have received a copy of the GNU General Public License along
 with this program; if not, write to the Free Software Foundation, 59 Temple
 Place - Suite 330, Boston, MA 02111-1307, USA.
 In other words, you are welcome to use, share and improve this program.
 You are forbidden to forbid anyone else to use, share and improve what
 you give them.
 Help stamp out software-hoarding! 
\end_layout

\begin_layout Section
Typographic conventions
\begin_inset LatexCommand \index{Typographic conventions}

\end_inset


\end_layout

\begin_layout Standard
Throughout this manual, we will use the following convention.
 Commands you have to type in are printed in 
\family sans
\series bold
"sans serif"
\series default
.

\family default
 Code samples are printed in 
\family typewriter
typewriter font.

\family default
 Interesting items and new terms are printed in 
\emph on
italic.
\end_layout

\begin_layout Section
Compatibility
\begin_inset LatexCommand \label{sec:Compatibility-with-previous}

\end_inset

 with previous versions
\begin_inset LatexCommand \index{Compatibility with previous versions}

\end_inset


\end_layout

\begin_layout Standard
Newer versions have usually numerous bug fixes compared with the previous
 version.
 But we also sometimes introduce some incompatibilities with older versions.
 Not just for the fun of it, but to make the compiler more stable, efficient
 and ANSI compliant
\begin_inset LatexCommand \index{ANSI-compliance}

\end_inset

 (see section 
\begin_inset LatexCommand \ref{sub:ANSI-Compliance}

\end_inset

 for ANSI-Compliance).
 
\begin_inset Note Note
status collapsed

\begin_layout Standard
It would be fine to add to each item, in which version was it changed.
\end_layout

\end_inset


\newline

\end_layout

\begin_layout Itemize
short is now equivalent to int (16 bits), it used to be equivalent to char
 (8 bits) which is not ANSI compliant.
 To maintain compatibility, old programs may be compiled using the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-short-is-8bits commandline option (see 
\begin_inset LatexCommand \vref{lyx:--short-is-8bits}

\end_inset

).
\end_layout

\begin_layout Itemize
the default directory for gcc-builds where include, library and documentation
 files are stored is now in /usr/local/share.
\end_layout

\begin_layout Itemize
char type parameters to vararg
\begin_inset LatexCommand \index{vararg, va\_arg}

\end_inset

 functions are casted to int unless explicitly casted and 
\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c89
\begin_inset LatexCommand \index{-\/-std-c89}

\end_inset

 
\series default
and
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c99
\begin_inset LatexCommand \index{-\/-std-c99}

\end_inset


\series default
 command line option are not defined 
\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
\InsetSpace ~
!
\end_layout

\end_inset

, e.g.: 
\newline

\family typewriter
\InsetSpace ~
\InsetSpace ~
char a=3;
\newline
\InsetSpace ~
\InsetSpace ~
printf ("%d %c
\backslash
n", a, (char)a);
\family default

\newline
 will push a as an int and as a char resp if
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c89
\begin_inset LatexCommand \index{-\/-std-c89}

\end_inset

 
\series default
and
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c99
\begin_inset LatexCommand \index{-\/-std-c99}

\end_inset


\series default
 command line options are not defined,
\newline
 will push a as two ints if
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c89
\begin_inset LatexCommand \index{-\/-std-c89}

\end_inset

 
\series default
or
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c99
\begin_inset LatexCommand \index{-\/-std-c99}

\end_inset


\series default
 command line option is defined.
\end_layout

\begin_layout Itemize
option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-regextend has been removed.
\end_layout

\begin_layout Itemize
option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-noregparms has been removed.
\end_layout

\begin_layout Itemize
option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-after-data has been removed.
\end_layout

\begin_layout Itemize
bit
\begin_inset LatexCommand \index{bit}

\end_inset

 and sbit
\begin_inset LatexCommand \index{sbit}

\end_inset


\begin_inset LatexCommand \index{\_\_sbit}

\end_inset

 types now consistently behave like the C99 _Bool type with respect to type
 conversion
\begin_inset LatexCommand \index{type conversion}

\end_inset


\begin_inset LatexCommand \index{type promotion}

\end_inset

.
 The most common incompatibility resulting from this change is related to
 bit toggling
\begin_inset LatexCommand \index{Bit toggling}

\end_inset

 idioms, e.g.:
\newline

\family typewriter
\InsetSpace ~
\InsetSpace ~
bit b;
\newline
\InsetSpace ~
\InsetSpace ~
b = ~
\begin_inset LatexCommand \index{\~\/ Operator}

\end_inset

b; /* equivalent to b=1 instead of toggling b */
\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
\InsetSpace ~
!
\end_layout

\end_inset


\newline
\InsetSpace ~
\InsetSpace ~
b = !b; /* toggles b */
\newline

\family default
In previous versions, both forms would have toggled the bit.
\end_layout

\begin_layout Standard

\emph on
<pending: more incompatibilities?>
\end_layout

\begin_layout Section
System Requirements
\end_layout

\begin_layout Standard
What do you need before you start installation of SDCC? A computer, and
 a desire to compute.
 The preferred method of installation is to compile SDCC from source using
 GNU gcc and make.
 For Windows some pre-compiled binary distributions are available for your
 convenience.
 You should have some experience with command line tools and compiler use.
\end_layout

\begin_layout Section
Other Resources
\end_layout

\begin_layout Standard
The SDCC home page at 
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}

\end_inset

 is a great place to find distribution sets.
 You can also find links to the user mailing lists that offer help or discuss
 SDCC with other SDCC users.
 Web links to other SDCC related sites can also be found here.
 This document can be found in the DOC directory of the source package as
 a text or HTML file.
 A pdf version of this document is available at 
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/sdccman.pdf}

\end_inset

.
 Some of the other tools (simulator and assembler) included with SDCC contain
 their own documentation and can be found in the source distribution.
 If you want the latest unreleased software, the complete source package
 is available directly from Subversion on https://sdcc.svn.sourceforge.net/svnroot/
sdcc/trunk/sdcc.
\end_layout

\begin_layout Section
Wishes for the future
\end_layout

\begin_layout Standard
There are (and always will be) some things that could be done.
 Here are some I can think of:
\newline

\end_layout

\begin_layout Standard

\family typewriter
char KernelFunction3(char p) at 0x340;
\newline

\end_layout

\begin_layout Standard

\family typewriter
better code banking
\begin_inset LatexCommand \index{code banking (limited support)}

\end_inset

 support for mcs51
\newline

\newline

\family default
If you can think of some more, please see the section 
\begin_inset LatexCommand \ref{sub:Requesting-Features}

\end_inset

 about filing feature requests
\begin_inset LatexCommand \index{Requesting features}

\end_inset


\begin_inset LatexCommand \index{Feature request}

\end_inset

.
\newline

\end_layout

\begin_layout Chapter
Installing SDCC
\begin_inset LatexCommand \index{Installation}

\end_inset


\end_layout

\begin_layout Standard
For most users it is sufficient to skip to either section 
\begin_inset LatexCommand \ref{sub:Building-SDCC-on-Linux}

\end_inset

 (Unix) or section 
\begin_inset LatexCommand \ref{sub:Windows-Install}

\end_inset

 (Windows).
 More detailed instructions follow below.
\end_layout

\begin_layout Section
Configure Options
\begin_inset LatexCommand \index{Options SDCC configuration}

\end_inset


\end_layout

\begin_layout Standard
The install paths, search paths and other options are defined when running
 'configure'.
 The defaults can be overridden by:
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-prefix see table below
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-exec_prefix see table below
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-bindir see table below
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-datadir see table below
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-datarootdir see table below
\newline

\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
\InsetSpace ~
\InsetSpace ~
docdir environment variable, see table below
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
\InsetSpace ~
\InsetSpace ~
include_dir_suffix environment variable, see table below
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
\InsetSpace ~
\InsetSpace ~
lib_dir_suffix environment variable, see table below
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
\InsetSpace ~
\InsetSpace ~
sdccconf_h_dir_separator environment variable, either / or 
\backslash

\backslash
 makes sense here.
 This character will only be used in sdccconf.h; don't forget it's a C-header,
 therefore a double-backslash is needed there.
\newline

\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-mcs51-port Excludes the Intel mcs51 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-gbz80-port Excludes the Gameboy gbz80 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-z80-port Excludes the z80 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-avr-port Excludes the AVR port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-ds390-port Excludes the DS390 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-hc08-port Excludes the HC08 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-pic-port Excludes the PIC14 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-pic16-port Excludes the PIC16 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-xa51-port Excludes the XA51 port
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-ucsim Disables configuring and building of ucsim
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-device-lib Disables automatically building device libraries
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-packihx Disables building packihx
\newline

\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-enable-doc Build pdf, html and txt files from the lyx sources
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-enable-libgc Use the Bohem memory allocator.
 Lower runtime footprint.
\end_layout

\begin_layout Standard
Furthermore the environment variables CC, CFLAGS, ...
 the tools and their arguments can be influenced.
 Please see `configure -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-help' and the man/info pages of `configure' for details.
\newline

\newline
The names of the
 standard libraries STD_LIB, STD_INT_LIB, STD_LONG_LIB, STD_FP_LIB, STD_DS390_LI
B, STD_XA51_LIB and the environment variables SDCC_DIR_NAME, SDCC_INCLUDE_NAME,
 SDCC_LIB_NAME are defined by `configure' too.
 At the moment it's not possible to change the default settings (it was
 simply never required).
\newline

\newline
These configure options are compiled into the binaries,
 and can only be changed by rerunning 'configure' and recompiling SDCC.
 The configure options are written in 
\emph on
italics
\emph default
 to distinguish them from run time environment variables (see section search
 paths).
\newline

\newline
The settings for 
\begin_inset Quotes sld
\end_inset

Win32 builds
\begin_inset Quotes srd
\end_inset

 are used by the SDCC team to build the official Win32 binaries.
 The SDCC team uses Mingw32 to build the official Windows binaries, because
 it's
\end_layout

\begin_layout Enumerate
open source, 
\end_layout

\begin_layout Enumerate
a gcc compiler and last but not least
\end_layout

\begin_layout Enumerate
the binaries can be built by cross compiling on SDCC Distributed Compile
 Farm.
\end_layout

\begin_layout Standard
See the examples, how to pass the Win32 settings to 'configure'.
 The other Win32 builds using Borland, VC or whatever don't use 'configure',
 but a header file sdcc_vc_in.h is the same as sdccconf.h built by 'configure'
 for Win32.
\newline

\newline
These defaults are:
\newline

\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="9" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="0in">
<column alignment="block" valignment="top" leftline="true" width="0in">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Variable
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
default
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Win32 builds
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
PREFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
/usr/local
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\backslash
sdcc
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
EXEC_PREFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$PREFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$PREFIX
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
BINDIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$EXEC_PREFIX
\emph default
/bin
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$EXEC_PREFIX
\emph default

\backslash
bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
DATADIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATAROOTDIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATAROOTDIR
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
DATAROOTDIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$PREFIX
\emph default
/share
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$PREFIX
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
DOCDIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATAROOTDIR
\emph default
/sdcc/doc
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATAROOTDIR
\emph default

\backslash
doc
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
INCLUDE_DIR_SUFFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/include
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
include
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
LIB_DIR_SUFFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/lib
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
lib
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Standard
\noindent
'configure' also computes relative paths.
 This is needed for full relocatability of a binary package and to complete
 search paths (see section search paths below):
\newline
 
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="0in">
<column alignment="block" valignment="top" leftline="true" width="0in">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Variable (computed)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
default
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Win32 builds
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
BIN2DATA_DIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
../share
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
..
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
PREFIX2BIN_DIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
bin
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
bin
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
PREFIX2DATA_DIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
share/sdcc
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Standard
\noindent
Examples:
\end_layout

\begin_layout LyX-Code
./configure
\newline
./configure -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-prefix=
\begin_inset Quotes srd
\end_inset

/usr/bin
\begin_inset Quotes srd
\end_inset

 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-datarootdir=
\begin_inset Quotes srd
\end_inset

/usr/share
\begin_inset Quotes srd
\end_inset


\newline
./configure -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-avr-port -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-xa51-port
\end_layout

\begin_layout Standard
To cross compile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw
32'):
\end_layout

\begin_layout LyX-Code
./configure 
\backslash

\newline
CC=
\begin_inset Quotes srd
\end_inset

i586-mingw32msvc-gcc
\begin_inset Quotes srd
\end_inset

 CXX=
\begin_inset Quotes srd
\end_inset

i586-mingw32msvc-g++
\begin_inset Quotes srd
\end_inset

 
\backslash
 
\newline
RANLIB=
\begin_inset Quotes srd
\end_inset

i586-mingw32msvc-ranlib
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
STRIP=
\begin_inset Quotes srd
\end_inset

i586-mingw32msvc-strip
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-prefix=
\begin_inset Quotes srd
\end_inset

/sdcc
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-datarootdir=
\begin_inset Quotes srd
\end_inset

/sdcc
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
docdir=
\begin_inset Quotes srd
\end_inset


\backslash
${datarootdir}/doc
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
include_dir_suffix=
\begin_inset Quotes srd
\end_inset

include
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
lib_dir_suffix=
\begin_inset Quotes srd
\end_inset

lib
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
sdccconf_h_dir_separator=
\begin_inset Quotes srd
\end_inset


\backslash

\backslash

\backslash

\backslash

\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-device-lib
\backslash

\newline
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-host=i586-mingw32msvc
\backslash

\newline
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-build=unknown-unknown-linux-gnu
\end_layout

\begin_layout Standard
To 
\begin_inset Quotes sld
\end_inset

cross
\begin_inset Quotes srd
\end_inset

compile on Cygwin for Mingw32 (see also sdcc/support/scripts/sdcc_cygwin_mingw32
):
\end_layout

\begin_layout LyX-Code
./configure -C 
\backslash

\newline
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-prefix=
\begin_inset Quotes srd
\end_inset

/sdcc
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-datarootdir=
\begin_inset Quotes srd
\end_inset

/sdcc
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
docdir=
\begin_inset Quotes srd
\end_inset


\backslash
${datarootdir}/doc
\begin_inset Quotes srd
\end_inset

 
\backslash
 
\newline
include_dir_suffix=
\begin_inset Quotes srd
\end_inset

include
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
lib_dir_suffix=
\begin_inset Quotes srd
\end_inset

lib
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
sdccconf_h_dir_separator=
\begin_inset Quotes srd
\end_inset


\backslash

\backslash

\backslash

\backslash

\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
CC=
\begin_inset Quotes srd
\end_inset

gcc -mno-cygwin
\begin_inset Quotes srd
\end_inset

 
\backslash

\newline
CXX=
\begin_inset Quotes srd
\end_inset

g++ -mno-cygwin
\begin_inset Quotes srd
\end_inset

 
\end_layout

\begin_layout Standard
'configure' is quite slow on Cygwin (at least on windows before Win2000/XP).
 The option '-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-C' turns on caching, which gives a little bit extra speed.
 However if options are changed, it can be necessary to delete the config.cache
 file.
\end_layout

\begin_layout Section
Install paths
\begin_inset LatexCommand \label{sub:Install-paths}

\end_inset


\begin_inset LatexCommand \index{Install paths}

\end_inset


\end_layout

\begin_layout Standard
\begin_inset VSpace medskip
\end_inset


\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="5" columns="4">
<features>
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Description
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Path
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Default
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Win32 builds
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Binary files*
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$EXEC_PREFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
/usr/local/bin
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\backslash
sdcc
\backslash
bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Include files
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATADIR/ $INCLUDE_DIR_SUFFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
/usr/local/share/sdcc/include
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\backslash
sdcc
\backslash
include
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Library file**
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATADIR/$LIB_DIR_SUFFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
/usr/local/share/sdcc/lib
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\backslash
sdcc
\backslash
lib
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Documentation
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DOCDIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
/usr/local/share/sdcc/doc
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\backslash
sdcc
\backslash
doc
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Verse

\size footnotesize
*compiler, preprocessor, assembler, and linker
\newline
**the 
\shape italic
model
\shape default
 is auto-appended by the compiler, e.g.
 small, large, z80, ds390 etc
\end_layout

\begin_layout Standard
\noindent
The install paths can still be changed during `make install' with e.g.:
\end_layout

\begin_layout LyX-Code
make install prefix=$(HOME)/local/sdcc
\end_layout

\begin_layout Standard
Of course this doesn't change the search paths compiled into the binaries.
\newline

\newline
Moreove
r the install path can be changed by defining DESTDIR
\begin_inset LatexCommand \index{DESTDIR}

\end_inset

:
\end_layout

\begin_layout LyX-Code
make install DESTDIR=$(HOME)/sdcc.rpm/
\end_layout

\begin_layout Standard
Please note that DESTDIR must have a trailing slash!
\end_layout

\begin_layout Section
Search Paths
\begin_inset LatexCommand \label{sub:Search-Paths}

\end_inset


\begin_inset LatexCommand \index{Search path}

\end_inset


\end_layout

\begin_layout Standard
Some search paths or parts of them are determined by configure variables
 (in 
\emph on
italics
\emph default
, see section above).
 Further search paths are determined by environment variables during runtime.
 
\newline
The paths searched when running the compiler are as follows (the first
 catch wins):
\newline

\newline
1.
 Binary files (preprocessor, assembler and linker)
\newline

\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="0in">
<column alignment="block" valignment="top" leftline="true" width="0in">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Search path
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
default
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Win32 builds
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME/
\emph on
$PPREFIX2BIN_DIR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME/bin
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME
\backslash
bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Path of argv[0] (if available)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Path of argv[0]
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Path of argv[0]
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$PATH
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$PATH
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$PATH
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset

 
\newline

\end_layout

\begin_layout Standard
\noindent
2.
 Include files
\newline

\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="1.5in">
<column alignment="block" valignment="top" leftline="true" width="1.5in">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Search path
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
default
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Win32 builds
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-I dir
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-I dir
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-I dir
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_INCLUDE
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_INCLUDE
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_INCLUDE
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME/
\newline

\emph on
$PREFIX2DATA_DIR/
\newline
$INCLUDE_DIR_SUFFIX
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_ HOME/
\newline
share/sdcc/
\newline
include
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME
\backslash
include
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
path(argv[0])/
\newline

\emph on
$BIN2DATADIR/
\emph default

\newline

\emph on
$INCLUDE_DIR_SUFFIX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
path(argv[0])/
\newline
../sdcc/include
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
path(argv[0])
\backslash
..
\backslash
include
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATADIR/
\emph default

\newline

\emph on
$INCLUDE_DIR_SUFFIX
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
/usr/local/share/sdcc/
\newline
include
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
(not on Win32)
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset

 
\newline

\end_layout

\begin_layout Standard
\noindent
The option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nostdinc disables the last two search paths.
\newline

\newline
3.
 Library files 
\newline

\end_layout

\begin_layout Standard
With the exception of 
\begin_inset Quotes sld
\end_inset

-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-L dir
\begin_inset Quotes srd
\end_inset

 the 
\shape italic
model
\shape default
 is auto-appended by the compiler (e.g.
 small, large, z80, ds390 etc.).
 
\newline

\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="1.7in">
<column alignment="block" valignment="top" leftline="true" width="1.2in">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="1.2in">
<row topline="true" bottomline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Search path
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
default
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Win32 builds
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-L dir
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-L dir
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-L dir
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_LIB/
\newline

\emph on
<model>
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_LIB/
\newline

\emph on
<model>
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_LIB
\backslash

\newline

\emph on
<model>
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME/
\newline

\emph on
$PREFIX2DATA_DIR/
\newline
$LIB_DIR_SUFFIX/<model>
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME/
\newline
share/sdcc/
\newline
lib/
\emph on
<model>
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
$SDCC_HOME
\backslash
lib
\backslash

\emph on

\newline
<model>
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
path(argv[0])/
\newline

\emph on
$BIN2DATADIR/
\emph default

\newline

\emph on
$LIB_DIR_SUFFIX/<model>
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
path(argv[0])/
\newline
../sdcc/lib/
\emph on
<model>
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
path(argv[0])
\backslash

\newline
..
\backslash
lib
\backslash

\emph on
<model>
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
$DATADIR/
\newline
$LIB_DIR_SUFFIX/<model>
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
/usr/local/share/sdcc/
\newline
lib/
\emph on
<model>
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
(not on Win32)
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
Don't delete any of the stray spaces in the table above without checking
 the HTML output (last line)!
\end_layout

\end_inset


\end_layout

\begin_layout Standard
\InsetSpace ~

\newline
The option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nostdlib disables the last two search paths.
\end_layout

\begin_layout Section
Building SDCC
\begin_inset LatexCommand \index{Building SDCC}

\end_inset


\end_layout

\begin_layout Subsection
Building SDCC on Linux
\begin_inset LatexCommand \label{sub:Building-SDCC-on-Linux}

\end_inset


\end_layout

\begin_layout Enumerate

\series medium
Download the source package
\series default
 either from the SDCC Subversion repository or from snapshot builds
\series medium
, it will be named something like sdcc
\series default
-src
\series medium
-yyyymmdd-rrrr.t
\series default
ar.
\series medium
bz2
\series default
 
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}

\end_inset

.
\end_layout

\begin_layout Enumerate

\series medium
Bring up a command line terminal, such as xterm.
\end_layout

\begin_layout Enumerate

\series medium
Unpack the file using a command like: 
\family sans
\series bold
"tar -xvzf sdcc-src-yyyymmdd-rrrr.tar.bz2
\begin_inset Quotes srd
\end_inset


\family default
\series medium
, this will create a sub-directory called sdcc with all of the sources.
\end_layout

\begin_layout Enumerate
Change directory into the main SDCC directory, for example type: 
\family sans
\series bold
"cd sdcc
\series default
".
\end_layout

\begin_layout Enumerate

\series medium
Type 
\family sans
\series bold
"./configure
\family default
\series default
".
 This configures the package for compilation on your system.
\end_layout

\begin_layout Enumerate

\series medium
Type 
\family sans
\series bold
"make
\family default
\series default
"
\series medium
.

\series default
 All of the source packages will compile, this can take a while.
\end_layout

\begin_layout Enumerate

\series medium
Type 
\family sans
\series bold
"make install"
\family default
\series default
 as root
\series medium
.

\series default
 This copies the binary executables, the include files, the libraries and
 the documentation to the install directories.
 Proceed with section 
\begin_inset LatexCommand \ref{sec:Testing-the-SDCC}

\end_inset

.
\end_layout

\begin_layout Subsection
Building SDCC on Mac OS X
\end_layout

\begin_layout Standard
Follow the instruction for Linux.
\newline

\newline
On Mac OS X 10.2.x it was reported, that the
 default gcc (version 3.1 20020420 (prerelease)) fails to compile SDCC.
 Fortunately there's also gcc 2.9.x installed, which works fine.
 This compiler can be selected by running 'configure' with:
\end_layout

\begin_layout LyX-Code
./configure CC=gcc2 CXX=g++2
\end_layout

\begin_layout Standard
Universal (ppc and i386) binaries can be produced on Mac OS X 10.4.x with
 Xcode.
 Run 'configure' with:
\end_layout

\begin_layout LyX-Code
./configure 
\backslash

\end_layout

\begin_layout LyX-Code
LDFLAGS="-Wl,-syslibroot,/Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch
 ppc" 
\backslash

\end_layout

\begin_layout LyX-Code
CXXFLAGS = "-O2 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch
 ppc" 
\backslash

\end_layout

\begin_layout LyX-Code
CFLAGS = "-O2 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch ppc"
\end_layout

\begin_layout Subsection
Cross compiling SDCC on Linux for Windows
\end_layout

\begin_layout Standard
With the Mingw32 gcc cross compiler it's easy to compile SDCC for Win32.
 See section 'Configure Options'.
\end_layout

\begin_layout Subsection
Building SDCC using Cygwin and Mingw32
\end_layout

\begin_layout Standard
For building and installing a Cygwin executable follow the instructions
 for Linux.
\newline

\newline
On Cygwin a 
\begin_inset Quotes sld
\end_inset

native
\begin_inset Quotes srd
\end_inset

 Win32-binary can be built, which will not need the Cygwin-DLL.
 For the necessary 'configure' options see section 'configure options' or
 the script 'sdcc/support/scripts/sdcc_cygwin_mingw32'.
\newline

\newline
In order to install
 Cygwin on Windows download setup.exe from 
\begin_inset LatexCommand \url[www.cygwin.com]{http://www.cygwin.com/}

\end_inset

.
 Run it, set the 
\begin_inset Quotes sld
\end_inset

default text file type
\begin_inset Quotes srd
\end_inset

 to 
\begin_inset Quotes sld
\end_inset

unix
\begin_inset Quotes srd
\end_inset

 and download/install at least the following packages.
 Some packages are selected by default, others will be automatically selected
 because of dependencies with the manually selected packages.
 Never deselect these packages!
\end_layout

\begin_layout Itemize
flex
\end_layout

\begin_layout Itemize
bison
\end_layout

\begin_layout Itemize
gcc ; version 3.x is fine, no need to use the old 2.9x
\end_layout

\begin_layout Itemize
binutils ; selected with gcc
\end_layout

\begin_layout Itemize
make
\end_layout

\begin_layout Itemize
rxvt ; a nice console, which makes life much easier under windoze (see below)
\end_layout

\begin_layout Itemize
man ; not really needed for building SDCC, but you'll miss it sooner or
 later
\end_layout

\begin_layout Itemize
less ; not really needed for building SDCC, but you'll miss it sooner or
 later
\end_layout

\begin_layout Itemize
svn ; only if you use Subversion access
\end_layout

\begin_layout Standard
If you want to develop something you'll need:
\end_layout

\begin_layout Itemize
python ; for the regression tests
\end_layout

\begin_layout Itemize
gdb ; the gnu debugger, together with the nice GUI 
\begin_inset Quotes sld
\end_inset

insight
\begin_inset Quotes srd
\end_inset


\end_layout

\begin_layout Itemize
openssh ; to access the CF or commit changes
\end_layout

\begin_layout Itemize
autoconf and autoconf-devel ; if you want to fight with 'configure', don't
 use autoconf-stable!
\end_layout

\begin_layout Standard
rxvt is a nice console with history.
 Replace in your cygwin.bat the line
\end_layout

\begin_layout LyX-Code
bash -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-login -i 
\end_layout

\begin_layout Standard
with (one line):
\end_layout

\begin_layout LyX-Code
rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
\end_layout

\begin_layout LyX-Code
     -bg black -fg white -geometry 100x65 -e bash -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-login
\end_layout

\begin_layout Standard
Text selected with the mouse is automatically copied to the clipboard, pasting
 works with shift-insert.
\newline

\newline
The other good tip is to make sure you have no //c/-styl
e paths anywhere, use /cygdrive/c/ instead.
 Using // invokes a network lookup which is very slow.
 If you think 
\begin_inset Quotes sld
\end_inset

cygdrive
\begin_inset Quotes srd
\end_inset

 is too long, you can change it with e.g.
\end_layout

\begin_layout LyX-Code
mount -s -u -c /mnt
\end_layout

\begin_layout Standard
SDCC sources use the unix line ending LF.
 Life is much easier, if you store the source tree on a drive which is mounted
 in binary mode.
 And use an editor which can handle LF-only line endings.
 Make sure not to commit files with windows line endings.
 The tabulator spacing
\begin_inset LatexCommand \index{tabulator spacing (8 columns)}

\end_inset

 used in the project is 8.
 Although a tabulator spacing of 8 is a sensible choice for programmers
 (it's a power of 2 and allows to display 8/16 bit signed variables without
 loosing columns) the plan is to move towards using only spaces in the source.
\end_layout

\begin_layout Subsection
Building SDCC Using Microsoft Visual C++ 6.0/NET (MSVC)
\end_layout

\begin_layout Standard

\series medium
Download the source package
\series default
 either from the SDCC Subversion repository or from the 
\begin_inset LatexCommand \url[snapshot builds]{http://sdcc.sourceforge.net/snap.php}

\end_inset


\series medium
, it will be named something like sdcc
\series default
-src
\series medium
-yyyymmdd-rrrr.tar.bz2.

\series default
 SDCC is distributed with all the projects, workspaces, and files you need
 to build it using Visual C++ 6.0/NET (except for SDCDB and ucSim).
 The workspace name is 'sdcc.dsw'.
 Please note that as it is now, all the executables are created in a folder
 called sdcc
\backslash
bin_vc.
 Once built you need to copy the executables from sdcc
\backslash
bin_vc to sdcc
\backslash
bin before running SDCC.
 
\newline

\newline
WARNING: Visual studio is very picky with line terminations; it expects
 the 0x0d, 0x0a DOS style line endings, not the 0x0a Unix style line endings.
 When using the Subversion repository it's easiest to configure the svn
 client to convert automatically for you.
 If however you are getting a message such as "This makefile was not generated
 by Developer Studio etc.
 etc.
\begin_inset Quotes srd
\end_inset

 when opening the sdcc.dsw workspace or any of the *.dsp projects, then you
 need to convert the Unix style line endings to DOS style line endings.
 To do so you can use the 
\begin_inset Quotes sld
\end_inset

unix2dos
\begin_inset Quotes srd
\end_inset

 utility freely available on the internet.
 Doug Hawkins reported in the sdcc-user list that this works:
\newline

\newline
C:
\backslash
Programming
\backslash
SDCC> unix2dos sdcc.dsw
\newline
C:
\backslash
Programming
\backslash
SDCC> for /R %I in (*.dsp) do @unix2dos "%I"
\newline

\newline
In order to build SDCC with MSVC
 you need win32 executables of bison.exe, flex.exe, and gawk.exe.
 One good place to get them is 
\begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}

\end_inset


\newline

\newline
Download the file UnxUtils
\begin_inset LatexCommand \index{UnxUtils}

\end_inset

.zip.
 Now you have to install the utilities and setup MSVC so it can locate the
 required programs.
 Here there are two alternatives (choose one!):
\end_layout

\begin_layout Enumerate
The easy way:
\newline

\newline
a) Extract UnxUtils.zip to your C:
\backslash
 hard disk PRESERVING the original paths, otherwise bison won't work.
 (If you are using WinZip make certain that 'Use folder names' is selected)
\newline

\newline
b)
 In the Visual C++ IDE click Tools, Options, select the Directory tab, in
 'Show directories for:' select 'Executable files', and in the directories
 window add a new path: 'C:
\backslash
user
\backslash
local
\backslash
wbin', click ok.
\newline

\newline
(As a side effect, you get a bunch of Unix utilities that
 could be useful, such as diff and patch.)
\end_layout

\begin_layout Enumerate
A more compact way:
\newline

\newline
This one avoids extracting a bunch of files you may not
 use, but requires some extra work:
\newline

\newline
a) Create a directory were to put the
 tools needed, or use a directory already present.
 Say for example 'C:
\backslash
util'.
\newline

\newline
b) Extract 'bison.exe', 'bison.hairy', 'bison.simple', 'flex.exe', and
 gawk.exe to such directory WITHOUT preserving the original paths.
 (If you are using WinZip make certain that 'Use folder names' is not selected)
\newline

\newline
c
) Rename bison.exe to '_bison.exe'.
\newline

\newline
d) Create a batch file 'bison.bat' in 'C:
\backslash
util
\backslash
' and add these lines: 
\newline
\InsetSpace ~
\InsetSpace ~
set BISON_SIMPLE=C:
\backslash
util
\backslash
bison.simple 
\newline
\InsetSpace ~
\InsetSpace ~
set BISON_HAIRY=C:
\backslash
util
\backslash
bison.hairy
\newline
\InsetSpace ~
\InsetSpace ~
_bison %1 %2 %3 %4 %5 %6 %7 %8 %9
\newline

\newline
Steps 'c' and 'd' are needed
 because bison requires by default that the files 'bison.simple' and 'bison.hairy'
 reside in some weird Unix directory, '/usr/local/share/' I think.
 So it is necessary to tell bison where those files are located if they
 are not in such directory.
 That is the function of the environment variables BISON_SIMPLE and BISON_HAIRY.
\newline

\newline
e
) In the Visual C++ IDE click Tools, Options, select the Directory tab,
 in 'Show directories for:' select 'Executable files', and in the directories
 window add a new path: 'c:
\backslash
util', click ok.
 Note that you can use any other path instead of 'c:
\backslash
util', even the path where the Visual C++ tools are, probably: 'C:
\backslash
Program Files
\backslash
Microsoft Visual Studio
\backslash
Common
\backslash
Tools'.
 So you don't have to execute step 'e' :)
\end_layout

\begin_layout Standard
That is it.
 Open 'sdcc.dsw' in Visual Studio, click 'build all', when it finishes copy
 the executables from sdcc
\backslash
bin_vc to sdcc
\backslash
bin, and you can compile using SDCC.
\end_layout

\begin_layout Subsection
Building SDCC Using Borland
\end_layout

\begin_layout Enumerate
From the sdcc directory, run the command "make -f Makefile.bcc".
 This should regenerate all the .exe files in the bin directory except for
 SDCDB and ucSim.
\end_layout

\begin_layout Enumerate
If you modify any source files and need to rebuild, be aware that the dependenci
es may not be correctly calculated.
 The safest option is to delete all .obj files and run the build again.
 From a Cygwin BASH prompt, this can easily be done with the command (be
 sure you are in the sdcc directory):
\newline

\newline

\family sans
\series bold
find .
 
\backslash
( -name '*.obj' -o -name '*.lib' -o -name '*.rul' 
\backslash
) -print -exec rm {} 
\backslash
;
\family default
\series default

\newline

\newline
or on Windows NT/2000/XP from the command prompt with the command:
\newline

\family sans
\series bold

\newline
del /s *.obj *.lib *.rul
\family default
\series default
 from the sdcc directory.
\end_layout

\begin_layout Subsection
Windows Install Using a ZIP Package
\end_layout

\begin_layout Enumerate
Download the binary zip package from 
\begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}

\end_inset

 and unpack it using your favorite unpacking tool (gunzip, WinZip, etc).
 This should unpack to a group of sub-directories.
 An example directory structure after unpacking the mingw32 package is:
 c:
\backslash
sdcc
\backslash
bin for the executables, c:
\backslash
sdcc
\backslash
include and c:
\backslash
sdcc
\backslash
lib for the include and libraries.
\end_layout

\begin_layout Enumerate
Adjust your environment variable PATH to include the location of the bin
 directory or start sdcc using the full path.
\end_layout

\begin_layout Subsection
Windows Install Using the Setup Program
\begin_inset LatexCommand \label{sub:Windows-Install}

\end_inset


\end_layout

\begin_layout Standard
Download the setup program 
\emph on
sdcc-x.y.z-setup.exe
\emph default
 for an official release from 
\newline

\begin_inset LatexCommand \url{http://sf.net/project/showfiles.php?group_id=599}

\end_inset

 or a setup program for one of the snapshots 
\emph on
sdcc-yyyymmdd-xxxx-setup.exe
\emph default
 from 
\begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}

\end_inset

 and execute it.
 A windows typical installer will guide you through the installation process.
\end_layout

\begin_layout Subsection
VPATH
\begin_inset LatexCommand \index{VPATH}

\end_inset

 feature
\end_layout

\begin_layout Standard
SDCC supports the VPATH feature provided by configure and make.
 It allows to separate the source and build trees.
 Here's an example:
\end_layout

\begin_layout Standard

\family typewriter
cd ~\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
# cd $HOME
\end_layout

\begin_layout Standard

\family typewriter
tar -xzf sdcc.src.tar.gz\InsetSpace ~
# extract source to directory sdcc
\end_layout

\begin_layout Standard

\family typewriter
mkdir sdcc.build\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
# put output in sdcc.build
\end_layout

\begin_layout Standard

\family typewriter
cd sdcc.build
\end_layout

\begin_layout Standard

\family typewriter
../sdcc/configure\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
# configure is doing all the magic!
\end_layout

\begin_layout Standard

\family typewriter
make
\end_layout

\begin_layout Standard
\noindent
That's it! 
\series bold
configure
\series default
 will create the directory tree will all the necessary Makefiles in ~/sdcc.build.
 It automagically computes the variables srcdir, top_srcdir and top_buildir
 for each directory.
 After running 
\series bold
make
\series default
 the generated files will be in ~/sdcc.build, while the source files stay
 in ~/sdcc.
\newline
This is not only usefull for building different binaries, e.g.
 when cross compiling.
 It also gives you a much better overview in the source tree when all the
 generated files are not scattered between the source files.
 And the best thing is: if you want to change a file you can leave the original
 file untouched in the source directory.
 Simply copy it to the build directory, edit it, enter `make clean', `rm
 Makefile.dep' and `make'.
 
\series bold
make
\series default
 will do the rest for you!
\end_layout

\begin_layout Section
Building the Documentation
\end_layout

\begin_layout Standard
Add -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-enable-doc to the configure arguments to build the documentation together
 with all the other stuff.
 You will need several tools (LyX, LaTeX, LaTeX2HTML, pdflatex, dvipdf,
 dvips and makeindex) to get the job done.
 Another possibility is to change to the doc directory and to type 
\family sans
\series bold

\begin_inset Quotes srd
\end_inset

make
\begin_inset Quotes srd
\end_inset


\family default
\series default
 there.
 You're invited to make changes and additions to this manual (sdcc/doc/sdccman.ly
x).
 Using LyX 
\begin_inset LatexCommand \url{http://www.lyx.org}

\end_inset

 as editor is straightforward.
 Prebuilt documentation in html and pdf format is available from 
\begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}

\end_inset

.
\end_layout

\begin_layout Section
Reading the Documentation
\begin_inset LatexCommand \index{Documentation}

\end_inset


\end_layout

\begin_layout Standard
Currently reading the document in pdf format is recommended, as for unknown
 reason the hyperlinks are working there whereas in the html version they
 are not
\begin_inset Foot
status open

\begin_layout Standard
If you should know why please drop us a note
\end_layout

\end_inset

.
 
\newline
You'll find the pdf version
\begin_inset LatexCommand \index{PDF version of this document}

\end_inset

 at 
\begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.pdf}

\end_inset

.
 
\newline
A html version
\begin_inset LatexCommand \index{HTML version of this document}

\end_inset

 should be online at 
\begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.html/index.html}

\end_inset

.
\newline
This documentation is in some aspects different from a commercial documentation:
 
\end_layout

\begin_layout Itemize
It tries to document SDCC for several processor architectures in one document
 (commercially these probably would be separate documents/products).
 This document
\begin_inset LatexCommand \index{Status of documentation}

\end_inset

 currently matches SDCC for mcs51 and DS390 best and does give too few informati
on about f.e.
 Z80, PIC14, PIC16 and HC08.
\end_layout

\begin_layout Itemize
There are many references pointing away from this documentation.
 Don't let this distract you.
 If there f.e.
 was a reference like 
\begin_inset LatexCommand \url{http://www.opencores.org}

\end_inset

 together with a statement 
\begin_inset Quotes sld
\end_inset

some processors which are targetted by SDCC can be implemented in a 
\emph on
f
\emph default
ield 
\emph on
p
\emph default
rogrammable 
\emph on
g
\emph default
ate 
\emph on
a
\emph default
rray
\begin_inset LatexCommand \index{FPGA (field programmable gate array)}

\end_inset


\begin_inset Quotes srd
\end_inset

 or 
\begin_inset LatexCommand \url{http://sf.net/projects/fpgac}

\end_inset


\begin_inset LatexCommand \index{FpgaC ((subset of) C to FPGA compiler)}

\end_inset

 
\begin_inset Quotes sld
\end_inset

have you ever heard of an open source compiler that compiles a subset of
 C for an FPGA?
\begin_inset Quotes srd
\end_inset

 we expect you to have a quick look there and come back.
 If you read this you are on the right track.
\end_layout

\begin_layout Itemize
Some sections attribute more space to problems, restrictions and warnings
 than to the solution.
\end_layout

\begin_layout Itemize
The installation section and the section about the debugger is intimidating.
\end_layout

\begin_layout Itemize
There are still lots of typos and there are more different writing styles
 than pictures.
\end_layout

\begin_layout Section
Testing the SDCC Compiler
\begin_inset LatexCommand \label{sec:Testing-the-SDCC}

\end_inset


\end_layout

\begin_layout Standard
The first thing you should do after installing your SDCC compiler is to
 see if it runs.
 Type 
\family sans
\series bold
"sdcc -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-version"
\begin_inset LatexCommand \index{version}

\end_inset


\family default
\series default
 at the prompt, and the program should run and output its version like:
 
\newline

\family typewriter
SDCC : mcs51/z80/avr/ds390/pic16/pic14/ds400/hc08 2.5.6 #4169 (May 8 2006)
 (UNIX)
\end_layout

\begin_layout Standard
If it doesn't run, or gives a message about not finding sdcc program, then
 you need to check over your installation.
 Make sure that the sdcc bin directory is in your executable search path
 defined by the PATH environment setting (
\series medium
see 
\series default
section 
\begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}

\end_inset

\InsetSpace ~

\series medium
Install trouble-shooting for suggestions
\series default
).
 Make sure that the sdcc program is in the bin folder, if not perhaps something
 did not install correctly.
\newline

\newline

\series medium
SDCC 
\series default
is commonly installed as described in section 
\begin_inset Quotes sld
\end_inset

Install and search paths
\begin_inset Quotes srd
\end_inset

.
\newline

\newline

\series medium
Make sure the compiler works on a very simple example.
 Type in the following test.c program using your favorite 
\series default
ASCII 
\series medium
editor:
\end_layout

\begin_layout Verse

\family typewriter
char test;
\newline

\newline
void main(void) {
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
test=0;
\newline
}
\end_layout

\begin_layout Standard

\series medium
Compile this using the following command: 
\family sans
\series bold
"sdcc -c test.c".

\family default
\series default
 
\series medium
If all goes well, the compiler will generate a test.asm and test.rel file.
 Congratulations, you've just compiled your first program with SDCC.
 We used the -c option to tell SDCC not to link the generated code, just
 to keep things simple for this step.
\series default

\newline

\newline

\series medium
The next step is to try it with the linker.
 Type in 
\family sans
\series bold
"sdcc test.c
\family default
\series default
"
\series medium
.
 If all goes well the compiler will link with the libraries and produce
 a test.ihx output file.
 If this step fails
\series default
 
\series medium
(no test.ihx, and the linker generates warnings), then the problem is most
 likely that 
\series default
SDCC
\series medium
 cannot find the 
\series default
/
\series medium
usr/local/share/sdcc/lib directory
\series default
 
\series medium
(see 
\series default
section 
\begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}

\end_inset

\InsetSpace ~

\series medium
Install trouble-shooting for suggestions).
\series default

\newline

\newline

\series medium
The final test is to ensure 
\series default
SDCC
\series medium
 can use the 
\series default
standard
\series medium
 header files and libraries.
 Edit test.c and change it to the following:
\end_layout

\begin_layout Verse

\family typewriter
#include <string.h>
\newline

\newline
char str1[10];
\newline

\newline
void main(void) {
\newline
\InsetSpace ~
\InsetSpace ~
strcpy(str1, "testing");
\newline
}
\end_layout

\begin_layout Standard

\series medium
Compile this by typing 
\family sans
\series bold
"sdcc test.c"
\family default
\series medium
.
 This should generate a test.ihx output file, and it should give no warnings
 such as not finding the string.h file.
 If it cannot find the string.h file, then the problem is that 
\series default
SDCC
\series medium
 cannot find the /usr/local/share/sdcc/include directory
\series default
 
\series medium
(see the 
\series default
section 
\begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}

\end_inset

\InsetSpace ~

\series medium
Install trouble-shooting section for suggestions).

\series default
 Use option 
\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-print-search-dirs
\series default

\begin_inset LatexCommand \index{-\/-print-search-dirs}

\end_inset

 to find exactly where SDCC is looking for the include and lib files.
\end_layout

\begin_layout Section
Install Trouble-shooting
\begin_inset LatexCommand \label{sub:Install-Trouble-shooting}

\end_inset


\begin_inset LatexCommand \index{Install trouble-shooting}

\end_inset


\end_layout

\begin_layout Subsection
If SDCC does not build correctly
\end_layout

\begin_layout Standard
A thing to try is starting from scratch by unpacking the .tgz source package
 again in an empty directory.
 Configure it like:
\newline

\newline

\family sans
\series bold
./configure 2>&1 | tee configure.log
\family default
\series default

\newline

\newline
and build it like:
\newline

\newline

\family sans
\series bold
make 2>&1 | tee make.log
\family default
\series default

\newline

\newline
If anything goes wrong, you can review the log files to locate the problem.
 Or a relevant part of this can be attached to an email that could be helpful
 when requesting help from the mailing list.
\end_layout

\begin_layout Subsection
What the 
\begin_inset Quotes sld
\end_inset

./configure
\begin_inset Quotes srd
\end_inset

 does
\end_layout

\begin_layout Standard
The 
\begin_inset Quotes sld
\end_inset

./configure
\begin_inset Quotes srd
\end_inset

 command is a script that analyzes your system and performs some configuration
 to ensure the source package compiles on your system.
 It will take a few minutes to run, and will compile a few tests to determine
 what compiler features are installed.
\end_layout

\begin_layout Subsection
What the 
\begin_inset Quotes sld
\end_inset

make
\begin_inset Quotes srd
\end_inset

 does
\end_layout

\begin_layout Standard
This runs the GNU make tool, which automatically compiles all the source
 packages into the final installed binary executables.
\end_layout

\begin_layout Subsection
What the 
\begin_inset Quotes sld
\end_inset

make install
\begin_inset Quotes erd
\end_inset

 command does.
\end_layout

\begin_layout Standard
This will install the compiler, other executables libraries and include
 files into the appropriate directories.
 See sections 
\begin_inset LatexCommand \ref{sub:Install-paths}

\end_inset

,\InsetSpace ~

\begin_inset LatexCommand \ref{sub:Search-Paths}

\end_inset

\InsetSpace ~
about install and search paths.
\newline
On most systems you will need super-user privilege
s to do this.
\end_layout

\begin_layout Section
Components of SDCC
\end_layout

\begin_layout Standard
SDCC is not just a compiler, but a collection of tools by various developers.
 These include linkers, assemblers, simulators and other components.
 Here is a summary of some of the components.
 Note that the included simulator and assembler have separate documentation
 which you can find in the source package in their respective directories.
 As SDCC grows to include support for other processors, other packages from
 various developers are included and may have their own sets of documentation.
\newline

\newline
You
 might want to look at the files which are installed in <installdir>.
 At the time of this writing, we find the following programs for gcc-builds:
\newline

 
\newline
In <installdir>/bin:
\end_layout

\begin_layout Itemize
sdcc - The compiler.
\end_layout

\begin_layout Itemize
sdcpp - The C preprocessor.
\end_layout

\begin_layout Itemize
asx8051 - The assembler for 8051 type processors.
\end_layout

\begin_layout Itemize
as-z80
\series bold
, 
\series default
as-gbz80 - The Z80 and GameBoy Z80 assemblers.
\end_layout

\begin_layout Itemize
aslink -The linker for 8051 type processors.
\end_layout

\begin_layout Itemize
link-z80
\series bold
, 
\series default
link-gbz80 - The Z80 and GameBoy Z80 linkers.
\end_layout

\begin_layout Itemize
s51 - The ucSim 8051 simulator.
\end_layout

\begin_layout Itemize
sdcdb - The source debugger.
\end_layout

\begin_layout Itemize
packihx - A tool to pack (compress) Intel hex files.
\end_layout

\begin_layout Standard
In <installdir>/share/sdcc/include
\end_layout

\begin_layout Itemize
the include files
\end_layout

\begin_layout Standard
In <installdir>/share/sdcc/lib
\end_layout

\begin_layout Itemize
the subdirs src and small, large, z80, gbz80 and ds390 with the precompiled
 relocatables.
\end_layout

\begin_layout Standard
In <installdir>/share/sdcc/doc
\end_layout

\begin_layout Itemize
the documentation
\end_layout

\begin_layout Standard
As development for other processors proceeds, this list will expand to include
 executables to support processors like AVR, PIC, etc.
\end_layout

\begin_layout Subsection
sdcc - The Compiler
\end_layout

\begin_layout Standard
This is the actual compiler, it in turn uses the c-preprocessor and invokes
 the assembler and linkage editor.
\end_layout

\begin_layout Subsection
sdcpp - The C-Preprocessor
\end_layout

\begin_layout Standard
The preprocessor
\begin_inset LatexCommand \index{sdcpp (preprocessor)}

\end_inset

 is a modified version of the GNU cpp
\begin_inset LatexCommand \index{cpp|see{sdcpp}}

\end_inset

 preprocessor 
\begin_inset LatexCommand \url{http://gcc.gnu.org/}

\end_inset

.
 The C preprocessor is used to pull in #include sources, process #ifdef
 statements, #defines and so on.
\end_layout

\begin_layout Subsection
as
\emph on
xxxx
\emph default
, aslink, link-
\emph on
xxx
\emph default
 - The Assemblers and Linkage Editors
\end_layout

\begin_layout Standard
This is retargettable assembler & linkage editor, it was developed by Alan
 Baldwin.
 John Hartman created the version for 8051, and I (Sandeep) have made some
 enhancements and bug fixes for it to work properly with SDCC.
\end_layout

\begin_layout Subsection
s51 - The Simulator
\end_layout

\begin_layout Standard
S51
\begin_inset LatexCommand \index{s51}

\end_inset

 is a free open source simulator developed by Daniel Drotos.
 The simulator is built as part of the build process.
 For more information visit Daniel's web site at: 
\begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}

\end_inset

.
 It currently supports the core mcs51, the Dallas DS80C390 and the Phillips
 XA51 family.
\end_layout

\begin_layout Subsection
sdcdb - Source Level Debugger
\end_layout

\begin_layout Standard
SDCDB
\begin_inset LatexCommand \index{SDCDB (debugger)}

\end_inset

 is the companion source level debugger.
 More about SDCDB in section 
\begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}

\end_inset

.
 The current version of the debugger uses Daniel's Simulator S51
\begin_inset LatexCommand \index{s51}

\end_inset

, but can be easily changed to use other simulators.
\end_layout

\begin_layout Chapter
Using SDCC
\end_layout

\begin_layout Section
Compiling
\end_layout

\begin_layout Subsection
Single Source File Projects
\end_layout

\begin_layout Standard
For single source file 8051 projects the process is very simple.
 Compile your programs with the following command 
\family sans
\series bold
"sdcc sourcefile.c".

\family default
\series default
 This will compile, assemble and link your source file.
 Output files are as follows:
\end_layout

\begin_layout Itemize
sourcefile.asm
\begin_inset LatexCommand \index{<file>.asm}

\end_inset

 - Assembler source
\begin_inset LatexCommand \index{Assembler source}

\end_inset

 file created by the compiler
\end_layout

\begin_layout Itemize
sourcefile.lst
\begin_inset LatexCommand \index{<file>.lst}

\end_inset

 - Assembler listing
\begin_inset LatexCommand \index{Assembler listing}

\end_inset

 file created by the Assembler
\end_layout

\begin_layout Itemize
sourcefile.rst
\begin_inset LatexCommand \index{<file>.rst}

\end_inset

 - Assembler listing
\begin_inset LatexCommand \index{Assembler listing}

\end_inset

 file updated with linkedit information, created by linkage editor
\end_layout

\begin_layout Itemize
sourcefile.sym
\begin_inset LatexCommand \index{<file>.sym}

\end_inset

 - symbol listing
\begin_inset LatexCommand \index{Symbol listing}

\end_inset

 for the sourcefile, created by the assembler
\end_layout

\begin_layout Itemize
sourcefile.rel
\begin_inset LatexCommand \index{<file>.rel}

\end_inset

 or sourcefile.o
\begin_inset LatexCommand \index{<file>.o}

\end_inset

 - Object file
\begin_inset LatexCommand \index{Object file}

\end_inset

 created by the assembler, input to Linkage editor
\end_layout

\begin_layout Itemize
sourcefile.map
\begin_inset LatexCommand \index{<file>.map}

\end_inset

 - The memory map
\begin_inset LatexCommand \index{Memory map}

\end_inset

 for the load module, created by the Linker
\end_layout

\begin_layout Itemize
sourcefile.mem
\begin_inset LatexCommand \index{<file>.mem}

\end_inset

 - A file with a summary of the memory usage
\end_layout

\begin_layout Itemize
sourcefile.ihx
\begin_inset LatexCommand \index{<file>.ihx}

\end_inset

 - The load module in Intel hex format
\begin_inset LatexCommand \index{Intel hex format}

\end_inset

 (you can select the Motorola S19 format
\begin_inset LatexCommand \index{Motorola S19 format}

\end_inset

 with -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-out-fmt-s19
\begin_inset LatexCommand \index{-\/-out-fmt-s19}

\end_inset

.
 If you need another format you might want to use 
\family sans
\shape italic
objdump
\family default
\shape default

\begin_inset LatexCommand \index{objdump (tool)}

\end_inset

 or
\family sans
\shape italic
 srecord
\family default
\shape default

\begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}

\end_inset


\begin_inset Note Note
status collapsed

\begin_layout Standard
hyperlinks needed
\end_layout

\end_inset

 - see also section 
\begin_inset LatexCommand \vref{sub:Postprocessing-the-Intel}

\end_inset

).
 Both formats are documented in the documentation of srecord
\begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}

\end_inset


\end_layout

\begin_layout Itemize
sourcefile.adb
\begin_inset LatexCommand \index{<file>.adb}

\end_inset

 - An intermediate file containing debug information needed to create the
 .cdb file (with -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug
\begin_inset LatexCommand \index{-\/-debug}

\end_inset

) 
\end_layout

\begin_layout Itemize
sourcefile.cdb
\begin_inset LatexCommand \index{<file>.cdb}

\end_inset

 - An optional file (with -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug) containing debug information.
 The format is documented in cdbfileformat.pdf
\end_layout

\begin_layout Itemize
sourcefile.
 - (no extension)
\begin_inset LatexCommand \index{<file> (no extension)}

\end_inset

 An optional AOMF or AOMF51
\begin_inset LatexCommand \index{AOMF, AOMF51}

\end_inset

 
\begin_inset LatexCommand \label{OMF file}

\end_inset

file containing debug information (generated with option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug).
 The (Intel)
\emph on
 a
\emph default
bsolute 
\emph on
o
\emph default
bject 
\emph on
m
\emph default
odule 
\emph on
f
\emph default
ormat is a subformat of the OMF51 format and is commonly used by third party
 tools (debuggers
\begin_inset LatexCommand \index{Debugger}

\end_inset

, simulators, emulators).
\end_layout

\begin_layout Itemize
sourcefile.dump*
\begin_inset LatexCommand \index{<file>.dump*}

\end_inset

 - Dump file to debug the compiler it self (generated with option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpall) (see section 
\begin_inset LatexCommand \ref{sub:Intermediate-Dump-Options}

\end_inset

\InsetSpace ~
 and section 
\begin_inset LatexCommand \ref{sub:The-anatomy-of}

\end_inset

\InsetSpace ~

\begin_inset Quotes sld
\end_inset

Anatomy of the compiler
\begin_inset Quotes srd
\end_inset

).
\end_layout

\begin_layout Subsection
Postprocessing the Intel Hex
\begin_inset LatexCommand \index{Intel hex format}

\end_inset

 file
\begin_inset LatexCommand \label{sub:Postprocessing-the-Intel}

\end_inset


\end_layout

\begin_layout Standard
In most cases this won't be needed but the Intel Hex file
\begin_inset LatexCommand \index{<file>.ihx}

\end_inset

 which is generated by SDCC might include lines of varying length and the
 addresses within the file are not guaranteed to be strictly ascending.
 If your toolchain or a bootloader does not like this you can use the tool
 
\family typewriter
packihx
\family default

\begin_inset LatexCommand \index{packihx (tool)}

\end_inset

 which is part of the SDCC distribution: 
\newline

\newline

\family sans
\series bold
 packihx sourcefile.ihx >sourcefile.hex
\family default
\series default

\newline

\newline
The separately available
\emph on
 srecord
\emph default

\begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}

\end_inset

 package additionally allows to set undefined locations to a predefined
 value, to insert checksums
\begin_inset LatexCommand \index{checksum}

\end_inset

 of various flavours (crc, add, xor) and to perform other manipulations
 (convert, split, crop, offset, ...).
 
\newline

\newline

\family sans
\series bold
srec_cat\InsetSpace ~
\InsetSpace ~
sourcefile.ihx -intel\InsetSpace ~
\InsetSpace ~
-o sourcefile.hex -intel
\newline

\newline

\family default
\series default
An example for a more complex command line
\begin_inset Foot
status open

\begin_layout Standard
the command backfills
\begin_inset LatexCommand \index{backfill unused memory}

\end_inset

 unused memory with 0x12 and the overall 16 bit sum of the complete 64 kByte
 block is zero.
 If the program counter on an mcs51 runs wild the backfill pattern 0x12
 will be interpreted as an 
\family typewriter
lcall
\family default
 to address 
\family typewriter
0x1212
\family default
 (where an emergency routine could sit).
\end_layout

\end_inset

 could look like:
\newline

\newline

\family sans
\series bold
\size footnotesize
srec_cat\InsetSpace ~
sourcefile.ihx -intel\InsetSpace ~
\InsetSpace ~
-fill 0x12 0x0000 0xfffe\InsetSpace ~
-little-endian-checksum-nega
tive 0xfffe 0x02 0x02\InsetSpace ~
\InsetSpace ~
-o sourcefile.hex -intel
\size default

\newline

\newline

\family default
\series default
The srecord package is available at 
\begin_inset LatexCommand \url{http://sf.net/projects/srecord}

\end_inset

 .
\end_layout

\begin_layout Subsection
Projects with Multiple Source Files
\end_layout

\begin_layout Standard
SDCC can compile only ONE file at a time.
 Let us for example assume that you have a project containing the following
 files:
\newline

\newline
foo1.c (contains some functions)
\newline
foo2.c (contains some more functions)
\newline
foomai
n.c (contains more functions and the function main)
\newline

\size footnotesize

\newline

\size default
The first two files will need to be compiled separately with the commands:
\size footnotesize
 
\size default

\newline

\newline

\family sans
\series bold
sdcc\InsetSpace ~
-c\InsetSpace ~
foo1.c
\family default
\series default
\size footnotesize

\newline

\family sans
\series bold
\size default
sdcc\InsetSpace ~
-c\InsetSpace ~
foo2.c
\family default
\series default

\newline

\newline
Then compile the source file containing the 
\emph on
main()
\emph default
 function and link
\begin_inset LatexCommand \index{Linker}

\end_inset

 the files together with the following command: 
\newline

\newline

\family sans
\series bold
sdcc\InsetSpace ~
foomain.c\InsetSpace ~
foo1.rel\InsetSpace ~
foo2.rel
\family default
\series default

\begin_inset LatexCommand \index{<file>.rel}

\end_inset


\newline

\newline
Alternatively, 
\emph on
foomain.c 
\emph default
can be separately compiled as well: 
\family sans
\series bold

\newline

\newline
sdcc\InsetSpace ~
-c\InsetSpace ~
foomain.c
\newline
sdcc foomain.rel foo1.rel foo2.rel
\newline

\newline

\family default
\series default
The file containing the 
\emph on
main()
\emph default
 function
\emph on
 
\emph default
\noun on
must
\noun default
 be the 
\noun on
first
\noun default
 file specified in the command line, since the linkage editor processes
 file in the order they are presented to it.
 The linker is invoked from SDCC using a script file with extension .lnk
\begin_inset LatexCommand \index{<file>.lnk}

\end_inset

.
 You can view this file to troubleshoot linking problems such as those arising
 from missing libraries.
\end_layout

\begin_layout Subsection
Projects with Additional Libraries
\begin_inset LatexCommand \index{Libraries}

\end_inset


\end_layout

\begin_layout Standard
Some reusable routines may be compiled into a library, see the documentation
 for the assembler and linkage editor (which are in <installdir>/share/sdcc/doc)
 for how to create a 
\emph on
.lib
\begin_inset LatexCommand \index{<file>.lib}

\end_inset


\emph default
 library file.
 Libraries created in this manner can be included in the command line.
 Make sure you include the -L <library-path> option to tell the linker where
 to look for these files if they are not in the current directory.
 Here is an example, assuming you have the source file 
\emph on
foomain.c
\emph default
 and a library
\emph on
 foolib.lib
\emph default
 in the directory 
\emph on
mylib
\emph default
 (if that is not the same as your current project):
\newline

\newline

\family sans
\series bold
sdcc foomain.c foolib.lib -L mylib
\newline

\newline

\family default
\series default
Note here that
\emph on
 mylib
\emph default
 must be an absolute path name.
\newline

\newline
The most efficient way to use libraries is
 to keep separate modules in separate source files.
 The lib file now should name all the modules.rel
\begin_inset LatexCommand \index{<file>.rel}

\end_inset

 files.
 For an example see the standard library file 
\emph on
libsdcc.lib
\emph default
 in the directory <installdir>/share/lib/small.
\end_layout

\begin_layout Subsection
Using sdcclib to Create and Manage Libraries
\begin_inset LatexCommand \index{sdcclib}

\end_inset


\end_layout

\begin_layout Standard
Alternatively, instead of having a .rel file for each entry on the library
 file as described in the preceding section, sdcclib can be used to embed
 all the modules belonging to such library in the library file itself.
 This results in a larger library file, but it greatly reduces the number
 of disk files accessed by the linker.
  Additionally, the packed library file contains an index of all include
 modules and symbols that significantly speeds up the linking process.
 To display a list of options supported by sdcclib type:
\newline

\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib -?
\begin_inset LatexCommand \index{sdcclib}

\end_inset


\newline

\newline

\family default
\series default
To create a new library file, start by compiling all the required modules.
 For example:
\newline

\end_layout

\begin_layout Standard

\family sans
\series bold
sdcc -c _divsint.c
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcc -c _divuint.c
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcc -c _modsint.c
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcc -c _moduint.c
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcc -c _mulint.c
\newline

\end_layout

\begin_layout Standard
This will create files _divsint.rel, _divuint.rel, _modsint.rel, _moduint.rel,
 and _mulint.rel.
 The next step is to add the .rel files to the library file:
\newline

\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib libint.lib _divsint.rel
\family default

\begin_inset LatexCommand \index{sdcclib}

\end_inset


\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib libint.lib _divuint.rel
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib libint.lib _modsint.rel
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib libint.lib _moduint.rel
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib libint.lib _mulint.rel
\family default
\series default

\newline

\end_layout

\begin_layout Standard
Or, if you preffer:
\family sans
\series bold

\newline

\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib libint.lib _divsint.rel _divuint.rel _modsint.rel _moduint.rel _mulint.rel
\family default
\series default

\newline

\end_layout

\begin_layout Standard
If the file already exists in the library, it will be replaced.
 If a list of .rel files is available, you can tell sdcclib to add those
 files to a library.
 For example, if the file 'myliblist.txt' contains
\family sans
\series bold

\newline

\end_layout

\begin_layout Standard

\family sans
\series bold
_divsint.rel
\end_layout

\begin_layout Standard

\family sans
\series bold
_divuint.rel
\end_layout

\begin_layout Standard

\family sans
\series bold
_modsint.rel
\end_layout

\begin_layout Standard

\family sans
\series bold
_moduint.rel
\end_layout

\begin_layout Standard

\family sans
\series bold
_mulint.rel
\family default
\series default

\newline

\end_layout

\begin_layout Standard
Use
\family sans
\series bold

\newline

\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib -l libint.lib myliblist.txt
\family default
\series default

\newline

\end_layout

\begin_layout Standard
Additionally, you can instruct sdcclib to compiles the files before adding
 them to the library.
 This is achieved using the environment variables SDCCLIB_CC and/or SDCCLIB_AS.
 For example:
\family sans
\series bold

\newline

\end_layout

\begin_layout Standard

\family sans
\series bold
set SDCCLIB_CC=sdcc -c
\end_layout

\begin_layout Standard

\family sans
\series bold
sdcclib -l libint.lib myliblist.txt
\family default
\series default

\newline

\end_layout

\begin_layout Standard
To see what modules and symbols are included in the library, options -s
 and -m are available.
 For example:
\newline

\newline

\family sans
\series bold
sdcclib -s libint.lib
\family default

\begin_inset LatexCommand \index{sdcclib}

\end_inset


\newline

\family typewriter
\series default
_divsint.rel:
\end_layout

\begin_layout Standard

\family typewriter
__divsint_a_1_1
\end_layout

\begin_layout Standard

\family typewriter
__divsint_PARM_2
\end_layout

\begin_layout Standard

\family typewriter
__divsint
\newline
_divuint.rel:
\end_layout

\begin_layout Standard

\family typewriter
__divuint_a_1_1
\end_layout

\begin_layout Standard

\family typewriter
__divuint_PARM_2
\end_layout

\begin_layout Standard

\family typewriter
__divuint_reste_1_1
\end_layout

\begin_layout Standard

\family typewriter
__divuint_count_1_1
\end_layout

\begin_layout Standard

\family typewriter
__divuint
\newline
_modsint.rel:
\end_layout

\begin_layout Standard

\family typewriter
__modsint_a_1_1
\end_layout

\begin_layout Standard

\family typewriter
__modsint_PARM_2
\end_layout

\begin_layout Standard

\family typewriter
__modsint
\newline
_moduint.rel:
\end_layout

\begin_layout Standard

\family typewriter
__moduint_a_1_1
\end_layout

\begin_layout Standard

\family typewriter
__moduint_PARM_2
\end_layout

\begin_layout Standard

\family typewriter
__moduint_count_1_1
\end_layout

\begin_layout Standard

\family typewriter
__moduint
\newline
_mulint.rel:
\end_layout

\begin_layout Standard

\family typewriter
__mulint_PARM_2
\end_layout

\begin_layout Standard

\family typewriter
__mulint
\family default
\series bold

\newline

\end_layout

\begin_layout Standard
If the source files are compiled using -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug
\begin_inset LatexCommand \index{-\/-debug}

\end_inset

, the corresponding debug information file .adb will be include in the library
 file as well.
 The library files created with sdcclib are plain text files, so they can
 be viewed with a text editor.
 It is not recomended to modify a library file created with sdcclib using
 a text editor, as there are file indexes numbers located accross the file
 used by the linker to quickly locate the required module to link.
 Once a .rel file (as well as a .adb file) is added to a library using sdcclib,
 it can be safely deleted, since all the information required for linking
 is embedded in the library file itself.
 Library files created using sdcclib are used as described in the preceding
 sections.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Command Line Options
\begin_inset LatexCommand \index{Command Line Options}

\end_inset


\begin_inset LatexCommand \label{sec:Command-Line-Options}

\end_inset


\end_layout

\begin_layout Subsection
Processor Selection Options
\begin_inset LatexCommand \index{Options processor selection}

\end_inset


\begin_inset LatexCommand \index{Processor selection options}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mmcs51
\begin_inset LatexCommand \index{-mmcs51}

\end_inset


\series default
 Generate code for the Intel MCS51
\begin_inset LatexCommand \index{MCS51}

\end_inset

 family of processors.
 This is the default processor target.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mds390
\begin_inset LatexCommand \index{-mds390}

\end_inset


\series default
 Generate code for the Dallas DS80C390
\begin_inset LatexCommand \index{DS80C390}

\end_inset

 processor.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mds400
\begin_inset LatexCommand \index{-mds400}

\end_inset


\series default
 Generate code for the Dallas DS80C400
\begin_inset LatexCommand \index{DS80C400}

\end_inset

 processor.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mhc08
\begin_inset LatexCommand \index{-mhc08}

\end_inset


\series default
 Generate code for the Freescale/Motorola HC08
\begin_inset LatexCommand \index{HC08}

\end_inset

 family of processors.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mz80
\begin_inset LatexCommand \index{-mz80}

\end_inset


\series default
 Generate code for the Zilog Z80
\begin_inset LatexCommand \index{Z80}

\end_inset

 family of processors.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mgbz80
\begin_inset LatexCommand \index{-mgbz80}

\end_inset


\series default
 Generate code for the GameBoy Z80
\begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}

\end_inset

 processor (Not actively maintained).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mavr
\begin_inset LatexCommand \index{-mavr}

\end_inset


\series default
 Generate code for the Atmel AVR
\begin_inset LatexCommand \index{AVR}

\end_inset

 processor (Not maintained, not complete).
 AVR users should probably have a look at winavr 
\begin_inset LatexCommand \url{http://sourceforge.net/projects/winavr}

\end_inset

 or 
\begin_inset LatexCommand \url{http://www.avrfreaks.net/index.php?name=PNphpBB2&file=index}

\end_inset

, which is based on AVR-port of the gcc compiler.
\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
I think it is fair to direct users there for now.
 Open source is also about avoiding unnecessary work .
 But I didn't find the 'official' link.
\end_layout

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mpic14
\begin_inset LatexCommand \index{-mpic14}

\end_inset


\series default
 Generate code for the Microchip PIC 14
\begin_inset LatexCommand \index{PIC14}

\end_inset

-bit processors (p16f84 and variants.
 In development, not complete).
\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
p16f627 p16f628 p16f84 p16f873 p16f877?
\end_layout

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mpic16
\begin_inset LatexCommand \index{-mpic16}

\end_inset


\series default
 Generate code for the Microchip PIC 16
\begin_inset LatexCommand \index{PIC16}

\end_inset

-bit processors (p18f452 and variants.
 In development, not complete).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mtlcs900h
\series default
 Generate code for the Toshiba TLCS-900H
\begin_inset LatexCommand \index{TLCS-900H}

\end_inset

 processor (Not maintained, not complete).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-mxa51
\begin_inset LatexCommand \index{-mxa51}

\end_inset


\series default
 Generate code for the Phillips XA51
\begin_inset LatexCommand \index{XA51}

\end_inset

 processor (Not maintained, not complete).
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Preprocessor Options
\begin_inset LatexCommand \index{Options preprocessor}

\end_inset


\begin_inset LatexCommand \index{Preprocessor options}

\end_inset


\begin_inset LatexCommand \index{sdcpp (preprocessor)}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-I<path>
\begin_inset LatexCommand \index{-I<path>}

\end_inset


\series default
 The additional location where the preprocessor will look for <..h> or 
\begin_inset Quotes eld
\end_inset

..h
\begin_inset Quotes erd
\end_inset

 files.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-D<macro[=value]>
\begin_inset LatexCommand \index{-D<macro[=value]>}

\end_inset


\series default
 Command line definition of macros.
 Passed to the preprocessor.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-M
\begin_inset LatexCommand \index{-M}

\end_inset


\series default
 Tell the preprocessor to output a rule suitable for make describing the
 dependencies of each object file.
 For each source file, the preprocessor outputs one make-rule whose target
 is the object file name for that source file and whose dependencies are
 all the files `#include'd in it.
 This rule may be a single line or may be continued with `
\backslash
'-newline if it is long.
 The list of rules is printed on standard output instead of the preprocessed
 C program.
 `-M' implies `-E
\begin_inset LatexCommand \index{-E}

\end_inset

'.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-C
\begin_inset LatexCommand \index{-C}

\end_inset


\series default
 Tell the preprocessor not to discard comments.
 Used with the `-E' option.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-MM
\begin_inset LatexCommand \index{-MM}

\end_inset


\size large
\bar under
 
\series default
\size default
\bar default
Like `-M' but the output mentions only the user header files included with
 `#include 
\begin_inset Quotes eld
\end_inset

file"'.
 System header files included with `#include <file>' are omitted.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-Aquestion(answer)
\begin_inset LatexCommand \index{-Aquestion(answer)}

\end_inset


\series default
 Assert the answer answer for question, in case it is tested with a preprocessor
 conditional such as `#if #question(answer)'.
 `-A-' disables the standard assertions that normally describe the target
 machine.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-Umacro
\begin_inset LatexCommand \index{-Umacro}

\end_inset


\series default
 Undefine macro macro.
 `-U' options are evaluated after all `-D' options, but before any `-include'
 and `-imacros' options.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-dM
\begin_inset LatexCommand \index{-dM}

\end_inset


\series default
 Tell the preprocessor to output only a list of the macro definitions that
 are in effect at the end of preprocessing.
 Used with the `-E' option.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-dD
\begin_inset LatexCommand \index{-dD}

\end_inset


\series default
 Tell the preprocessor to pass all macro definitions into the output, in
 their proper sequence in the rest of the output.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-dN
\begin_inset LatexCommand \index{-dN}

\end_inset


\size large
\bar under
 
\series default
\size default
\bar default
Like `-dD' except that the macro arguments and contents are omitted.
 Only `#define name' is included in the output.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-pedantic-parse-number
\begin_inset LatexCommand \index{pedantic}

\end_inset


\begin_inset LatexCommand \index{-pedantic-parse-number}

\end_inset


\size large
\bar under

\begin_inset LatexCommand \label{lyx:-pedantic-parse-number}

\end_inset

 
\series default
\size default
\bar default
Pedantic parse numbers so that situations like 0xfe-LO_B(3) are parsed properly
 and the macro LO_B(3) gets expanded.
 See also #pragma pedantic_parse_number 
\begin_inset LatexCommand \vpageref{ite:pedantic_parse_number}

\end_inset

 in section
\begin_inset LatexCommand \ref{sec:Pragmas}

\end_inset

 
\emph on
Note: this functionality is not in conformance with C99 standard!
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-Wp\InsetSpace ~
preprocessorOption[,preprocessorOption]
\series default

\begin_inset LatexCommand \index{-Wp preprocessorOption[,preprocessorOption]}

\end_inset

...
 Pass the preprocessorOption to the preprocessor 
\family typewriter
sdcpp
\family default

\begin_inset LatexCommand \index{sdcpp (preprocessor)}

\end_inset

.
 SDCC uses an adapted version of the preprocessor 
\emph on
cpp
\emph default
 of the GNU Compiler Collection
\begin_inset LatexCommand \index{gcc (GNU Compiler Collection)}

\end_inset

 (
\emph on
gcc
\emph default
 
\begin_inset LatexCommand \url{http://gcc.gnu.org/}

\end_inset

), if you need more dedicated options please refer to the GCC\InsetSpace ~
4.1.1\InsetSpace ~
CPP\InsetSpace ~
Manual
 at 
\begin_inset LatexCommand \htmlurl{http://www.gnu.org/software/gcc/onlinedocs/}

\end_inset

.
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Linker Options
\begin_inset LatexCommand \index{Options linker}

\end_inset


\begin_inset LatexCommand \index{Linker options}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-L\InsetSpace ~
-
\series default

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series bold
-lib-path
\begin_inset LatexCommand \index{-\/-lib-path <path>}

\end_inset


\begin_inset LatexCommand \index{-L -\/-lib-path}

\end_inset


\series default
\InsetSpace ~
<absolute path to additional libraries> This option is passed to the linkage
 editor's additional libraries
\begin_inset LatexCommand \index{Libraries}

\end_inset

 search path.
 The path name must be absolute.
 Additional library files may be specified in the command line.
 See section Compiling programs for more details.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xram-loc
\series default

\begin_inset LatexCommand \index{-\/-xram-loc <Value>}

\end_inset

\InsetSpace ~
<Value> The start location of the external ram
\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}

\end_inset

, default value is 0.
 The value entered can be in Hexadecimal or Decimal format, e.g.: -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xram-loc 0x8000 or -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xram-loc 32768.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-code-loc
\series default

\begin_inset LatexCommand \index{-\/-code-loc <Value>}

\end_inset

\InsetSpace ~
<Value> The start location of the code
\begin_inset LatexCommand \index{code}

\end_inset

 segment, default value 0.
 Note when this option is used the interrupt vector table
\begin_inset LatexCommand \index{interrupt vector table}

\end_inset

 is also relocated to the given address.
 The value entered can be in Hexadecimal or Decimal format, e.g.: -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-code-loc 0x8000 or -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-code-loc 32768.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-loc
\series default

\begin_inset LatexCommand \index{-\/-stack-loc <Value>}

\end_inset

\InsetSpace ~
<Value> By default the stack
\begin_inset LatexCommand \index{stack}

\end_inset

 is placed after the data segment.
 Using this option the stack can be placed anywhere in the internal memory
 space of the 8051.
 The value entered can be in Hexadecimal or Decimal format, e.g.
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-loc 0x20 or -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-loc 32.
 Since the sp register is incremented before a push or call, the initial
 sp will be set to one byte prior the provided value.
 The provided value should not overlap any other memory areas such as used
 register banks or the data segment and with enough space for the current
 application.
 The 
\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-pack-iram
\series default
\InsetSpace ~

\begin_inset LatexCommand \index{-\/-pack-iram}

\end_inset

 option (which is now a default setting) will override this setting, so
 you should also specify the 
\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-pack-iram
\series default
\InsetSpace ~

\begin_inset LatexCommand \index{-\/-no-pack-iram}

\end_inset

 option if you need to manually place the stack.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack-loc
\series default

\begin_inset LatexCommand \index{-\/-xstack-loc <Value>}

\end_inset

\InsetSpace ~
<Value> By default the external stack
\begin_inset LatexCommand \index{xstack}

\end_inset

 is placed after the pdata
\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}

\end_inset

 segment.
 Using this option the xstack can be placed anywhere in the external memory
 space of the 8051.
 The value entered can be in Hexadecimal or Decimal format, e.g.
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack-loc 0x8000 or -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-loc 32768.
 The provided value should not overlap any other memory areas such as the
 pdata or xdata segment and with enough space for the current application.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-data-loc
\series default

\begin_inset LatexCommand \index{-\/-data-loc <Value>}

\end_inset

\InsetSpace ~
<Value> The start location of the internal ram data
\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}

\end_inset

 segment.
 The value entered can be in Hexadecimal or Decimal format, eg.
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-data-loc 0x20 or -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-data-loc 32.
 (By default, the start location of the internal ram data segment  is set
 as low as possible in memory, taking into account the used register banks
 and the bit segment at address 0x20.
 For example if register banks 0 and 1 are used without bit variables, the
 data segment will be set, if -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-data-loc is not used, to location 0x10.)
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-idata-loc
\series default

\begin_inset LatexCommand \index{-\/-idata-loc <Value>}

\end_inset

\InsetSpace ~
<Value> The start location of the indirectly addressable internal ram
\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}

\end_inset

 of the 8051, default value is 0x80.
 The value entered can be in Hexadecimal or Decimal format, eg.
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-idata-loc 0x88 or -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-idata-loc 136.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-bit-loc
\series default
\InsetSpace ~
<Value> The start location of the bit
\begin_inset LatexCommand \index{bit}

\end_inset

 addressable internal ram of the 8051.
 This is 
\emph on
not
\emph default
 implemented yet.
 Instead an option can be passed directly to the linker: -Wl\InsetSpace ~
-bBSEG=<Value>.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-out-fmt-ihx
\begin_inset LatexCommand \index{-\/-out-fmt-ihx}

\end_inset


\bar under
 
\series default
\bar default
The linker output (final object code) is in Intel Hex format.
\begin_inset LatexCommand \index{Intel hex format}

\end_inset

 This is the default option.
 The format itself is documented in the documentation of srecord
\begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}

\end_inset

.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-out-fmt-s19
\begin_inset LatexCommand \index{-\/-out-fmt-s19}

\end_inset


\bar under
 
\series default
\bar default
The linker output (final object code) is in Motorola S19 format
\begin_inset LatexCommand \index{Motorola S19 format}

\end_inset

.
 The format itself is documented in the documentation of srecord.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-out-fmt-elf
\begin_inset LatexCommand \index{-\/-out-fmt-s19}

\end_inset


\begin_inset LatexCommand \index{HC08!Options!-\/-out-fmt-elf}

\end_inset


\bar under
 
\series default
\bar default
The linker output (final object code) is in ELF format
\begin_inset LatexCommand \index{ELF format}

\end_inset

.
 (Currently only supported for the HC08
\begin_inset LatexCommand \index{HC08}

\end_inset

 processors)
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-Wl\InsetSpace ~
linkOption[,linkOption]
\series default

\begin_inset LatexCommand \index{-Wl linkOption[,linkOption]}

\end_inset

\begin_inset LatexCommand \label{lyx:-Wl option}

\end_inset

...
 Pass the linkOption to the linker.
 If a bootloader is used an option like 
\begin_inset Quotes sld
\end_inset

-Wl\InsetSpace ~
-bCSEG=0x1000
\begin_inset Quotes srd
\end_inset

 would be typical to set the start of the code segment.
 Either use the double quotes around this option or use no space (e.g.
 -Wl-bCSEG=0x1000).
 See also #pragma constseg and #pragma codeseg in section 
\begin_inset LatexCommand \ref{sec:Pragmas}

\end_inset

 .
 File sdcc/as/doc/asxhtm.html has more on linker options.
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
MCS51 Options
\begin_inset LatexCommand \index{Options MCS51}

\end_inset


\begin_inset LatexCommand \index{MCS51 options}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-small
\begin_inset LatexCommand \index{-\/-model-small}

\end_inset


\series default
\size large
\emph on
 
\size default
\emph default
Generate code for Small Model programs, see section Memory Models for more
 details.
 This is the default model.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-medium
\begin_inset LatexCommand \index{-\/-model-medium}

\end_inset


\series default
 Generate code for Medium model programs, see section Memory Models for
 more details.
 If this option is used all source files in the project have to be compiled
 with this option.
 It must also be used when invoking the linker.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-large
\begin_inset LatexCommand \index{-\/-model-large}

\end_inset


\series default
 Generate code for Large model programs, see section Memory Models for more
 details.
 If this option is used all source files in the project have to be compiled
 with this option.
 It must also be used when invoking the linker.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack
\begin_inset LatexCommand \index{-\/-xstack}

\end_inset


\series default
 Uses a pseudo stack in the pdata
\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}

\end_inset

 area (usually the first 256 bytes in the external ram) for allocating variables
 and passing parameters.
 See section 
\begin_inset LatexCommand \ref{sub:External-Stack}

\end_inset

\InsetSpace ~
 External Stack for more details.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-iram-size
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{-\/-iram-size <Value>}

\end_inset

 Causes the linker to check if the internal ram usage is within limits of
 the given value.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xram-size
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{-\/-xram-size <Value>}

\end_inset

 Causes the linker to check if the external ram usage is within limits of
 the given value.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-code-size
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{-\/-code-size <Value>}

\end_inset

 Causes the linker to check if the code memory usage is within limits of
 the given value.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-size
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{-\/-stack-size <Value>}

\end_inset

 Causes the linker to check if there is at minimum <Value> bytes for stack.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-pack-iram
\series default
\InsetSpace ~

\begin_inset LatexCommand \index{-\/-pack-iram}

\end_inset

 Causes the linker to use unused register banks for data variables and pack
 data, idata and stack together.
 This is the default now.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-pack-iram
\series default
\InsetSpace ~

\begin_inset LatexCommand \index{-\/-no-pack-iram}

\end_inset

 Causes the linker to use old style for allocating memory areas.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-acall-ajmp
\series default
\InsetSpace ~

\begin_inset LatexCommand \index{-\/-acall-ajmp}

\end_inset

 Replaces the three byte instructions lcall/ljmp with the two byte instructions
 acall/ajmp.
 Only use this option if your code is in the same 2k block of memory.
 You may need to use this option for some 8051 derivatives which lack the
 lcall/ljmp instructions..
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
DS390 / DS400 Options
\begin_inset LatexCommand \index{Options DS390}

\end_inset


\begin_inset LatexCommand \index{DS390}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-flat24
\series default

\begin_inset LatexCommand \index{DS390!Options!-\/-model-flat24}

\end_inset


\size large
\emph on
 
\size default
\emph default
Generate 24-bit flat mode code.
 This is the one and only that the ds390 code generator supports right now
 and is default when using 
\emph on
-mds390
\emph default
.
 See section Memory Models for more details.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-protect-sp-update
\begin_inset LatexCommand \index{DS390!Options!-\/-protect-sp-update}

\end_inset


\series default
 disable interrupts during ESP:SP updates.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-10bit
\series default

\begin_inset LatexCommand \index{DS390!Options!-\/-stack-10bit}

\end_inset

 Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
 This is the one and only that the ds390 code generator supports right now
 and is default when using 
\emph on
-mds390
\emph default
.
 In this mode, the stack is located in the lower 1K of the internal RAM,
 which is mapped to 0x400000.
 Note that the support is incomplete, since it still uses a single byte
 as the stack pointer.
 This means that only the lower 256 bytes of the potential 1K stack space
 will actually be used.
 However, this does allow you to reclaim the precious 256 bytes of low RAM
 for use for the DATA and IDATA segments.
 The compiler will not generate any code to put the processor into 10 bit
 stack mode.
 It is important to ensure that the processor is in this mode before calling
 any re-entrant functions compiled with this option.
 In principle, this should work with the 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset


\emph default
 option, but that has not been tested.
 It is incompatible with the 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack
\begin_inset LatexCommand \index{-\/-xstack}

\end_inset


\emph default
 option.
 It also only makes sense if the processor is in 24 bit contiguous addressing
 mode (see the 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-flat24 option
\emph default
).
\series bold

\begin_inset Note Note
status collapsed

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-8-bit - switches off the 10-bit mode
\end_layout

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-probe
\begin_inset LatexCommand \index{DS390!Options!-\/-stack-probe}

\end_inset


\series default
 insert call to function __stack_probe at each function prologue.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-tini-libid
\begin_inset LatexCommand \index{DS390!Options!-\/-tini-libid}

\end_inset


\series default
 <nnnn> LibraryID used in -mTININative.
 
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-use-accelerator
\begin_inset LatexCommand \index{DS390!Options!-\/-use-accelerator}

\end_inset


\series default
 generate code for DS390 Arithmetic Accelerator.
 
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Z80 Options
\begin_inset LatexCommand \index{Options Z80}

\end_inset


\begin_inset LatexCommand \index{Z80}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves-bc
\series default

\begin_inset LatexCommand \index{Z80!Options!-\/-callee-saves-bc}

\end_inset


\size large
\emph on
 
\size default
\emph default
Force a called function to always save BC.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-std-crt0
\series default

\begin_inset LatexCommand \index{Z80!Options!-\/-no-std-crt0}

\end_inset

 When linking, skip the standard crt0.o object file.
 You must provide your own crt0.o for your system when linking.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-portmode=
\series default
<Value>
\begin_inset LatexCommand \index{Z80!Options!-\/-portmode=<Value>}

\end_inset

 Determinate PORT I/O mode (<Value> is z80 or z180).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-asm=
\series default
<Value>
\begin_inset LatexCommand \index{Z80!Options!-\/-asm=<Value>}

\end_inset

 Define assembler name (<Value> is rgbds, asxxxx, isas or z80asm).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-codeseg
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{Z80!Options!-\/-codeseg <Value>}

\end_inset

 Use <Value> for the code segment name.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-constseg
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{Z80!Options!-\/-constseg <Value>}

\end_inset

 Use <Value> for the const segment name.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
GBZ80 Options
\begin_inset LatexCommand \index{Options GBZ80}

\end_inset


\begin_inset LatexCommand \index{GBZ80}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves-bc
\series default

\begin_inset LatexCommand \index{GBZ80!Options!-\/-callee-saves-bc}

\end_inset


\size large
\emph on
 
\size default
\emph default
Force a called function to always save BC.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-std-crt0
\series default

\begin_inset LatexCommand \index{Z80!Options!-\/-no-std-crt0}

\end_inset

 When linking, skip the standard crt0.o object file.
 You must provide your own crt0.o for your system when linking.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-bo
\series default
\InsetSpace ~
<Num>
\begin_inset LatexCommand \index{GBZ80!Options!-bo <Num>}

\end_inset

 Use code bank <Num>.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-ba
\series default
\InsetSpace ~
<Num>
\begin_inset LatexCommand \index{GBZ80!Options!-ba <Num>}

\end_inset

 Use data bank <Num>.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-codeseg
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{GBZ80!Options!-\/-codeseg <Value>}

\end_inset

 Use <Value> for the code segment name.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-constseg
\series default
\InsetSpace ~
<Value>
\begin_inset LatexCommand \index{GBZ80!Options!-\/-constseg <Value>}

\end_inset

 Use <Value> for the const segment name.
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Optimization Options
\begin_inset LatexCommand \index{Options optimization}

\end_inset


\begin_inset LatexCommand \index{Optimization options}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nogcse
\begin_inset LatexCommand \index{-\/-nogcse}

\end_inset


\series default
 Will not do global subexpression elimination, this option may be used when
 the compiler creates undesirably large stack/data spaces to store compiler
 temporaries (
\emph on
s
\emph default
pill 
\emph on
loc
\emph default
ations, sloc
\begin_inset LatexCommand \index{sloc (spill location)}

\end_inset

).
 A warning message will be generated when this happens and the compiler
 will indicate the number of extra bytes it allocated.
 It is recommended that this option NOT be used, #pragma\InsetSpace ~
nogcse
\begin_inset LatexCommand \index{\#pragma nogcse}

\end_inset

 can be used to turn off global subexpression elimination
\begin_inset LatexCommand \index{Subexpression elimination}

\end_inset

 for a given function only.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-noinvariant
\begin_inset LatexCommand \index{-\/-noinvariant}

\end_inset


\series default
 Will not do loop invariant optimizations, this may be turned off for reasons
 explained for the previous option.
 For more details of loop optimizations performed see Loop Invariants in
 section 
\begin_inset LatexCommand \ref{sub:Loop-Optimizations}

\end_inset

.
 It is recommended that this option NOT be used, #pragma\InsetSpace ~
noinvariant
\begin_inset LatexCommand \index{\#pragma noinvariant}

\end_inset

 can be used to turn off invariant optimizations for a given function only.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-noinduction
\begin_inset LatexCommand \index{-\/-noinduction}

\end_inset


\series default
 Will not do loop induction optimizations, see section strength reduction
 for more details.
 It is recommended that this option is NOT used, #pragma\InsetSpace ~
noinduction
\begin_inset LatexCommand \index{\#pragma noinduction}

\end_inset

 can be used to turn off induction optimizations for a given function only.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nojtbound
\begin_inset LatexCommand \index{-\/-nojtbound}

\end_inset


\size large
\bar under
 
\series default
\size default
\bar default
 Will not generate boundary condition check when switch statements
\begin_inset LatexCommand \index{switch statement}

\end_inset

 are implemented using jump-tables.
 See section 
\begin_inset LatexCommand \ref{sub:'switch'-Statements}

\end_inset

\InsetSpace ~
Switch Statements for more details.
 It is recommended that this option is NOT used, #pragma\InsetSpace ~
nojtbound
\begin_inset LatexCommand \index{\#pragma nojtbound}

\end_inset

 can be used to turn off boundary checking for jump tables for a given function
 only.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-noloopreverse
\begin_inset LatexCommand \index{-\/-noloopreverse}

\end_inset


\series default
\size large
 
\size default
Will not do loop reversal 
\begin_inset LatexCommand \index{Loop reversing}

\end_inset

optimization.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-
\series bold
nolabelopt
\series default
 
\begin_inset LatexCommand \index{-\/-nolabelopt }

\end_inset

Will not optimize labels (makes the dumpfiles more readable).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-xinit-opt
\begin_inset LatexCommand \index{-\/-no-xinit-opt}

\end_inset


\series default
 Will not memcpy initialized data from code space into xdata space.
 This saves a few bytes in code space if you don't have initialized data
\begin_inset LatexCommand \index{Variable initialization}

\end_inset

.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nooverlay
\begin_inset LatexCommand \index{-\/-nooverlay}

\end_inset


\series default
  The compiler will not overlay parameters and local variables of any function,
 see section Parameters and local variables for more details.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-peep
\begin_inset LatexCommand \index{-\/-no-peep}

\end_inset


\series default
 Disable peep-hole optimization with built-in rules.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-peep-file
\series default

\begin_inset LatexCommand \index{-\/-peep-file}

\end_inset

\InsetSpace ~
<filename> This option can be used to use additional rules to be used by
 the peep hole optimizer.
 See section 
\begin_inset LatexCommand \ref{sub:Peephole-Optimizer}

\end_inset

\InsetSpace ~
Peep Hole optimizations for details on how to write these rules.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-peep-asm
\begin_inset LatexCommand \index{-\/-peep-asm}

\end_inset


\series default
 Pass the inline assembler code through the peep hole optimizer.
 This can cause unexpected changes to inline assembler code, please go through
 the peephole optimizer
\begin_inset LatexCommand \index{Peephole optimizer}

\end_inset

 rules defined in the source file tree '<target>/peeph.def' before using
 this option.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-opt-code-speed
\begin_inset LatexCommand \index{-\/-opt-code-speed}

\end_inset


\series default
 The compiler will optimize code generation towards fast code, possibly
 at the expense of code size.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-opt-code-size
\begin_inset LatexCommand \index{-\/-opt-code-size}

\end_inset


\series default
 The compiler will optimize code generation towards compact code, possibly
 at the expense of code speed.
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Other Options
\begin_inset LatexCommand \index{Options other}

\end_inset


\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-c\InsetSpace ~
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-compile-only
\begin_inset LatexCommand \index{-\/-compile-only}

\end_inset


\begin_inset LatexCommand \index{-c -\/-compile-only}

\end_inset


\series default
 will compile and assemble the source, but will not call the linkage editor.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\series default

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series bold
-c1mode
\begin_inset LatexCommand \index{-\/-c1mode}

\end_inset


\series default
 reads the preprocessed source from standard input and compiles it.
 The file name for the assembler output must be specified using the -o option.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-E
\begin_inset LatexCommand \index{-E}

\end_inset


\series default
 Run only the C preprocessor.
 Preprocess all the C source files specified and output the results to standard
 output.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-o\InsetSpace ~
<path/file>
\begin_inset LatexCommand \index{-o <path/file>}

\end_inset

 
\series default
The output path where everything will be placed or the file name used for
 all generated output files.
 If the parameter is a path, it must have a trailing slash (or backslash
 for the Windows binaries) to be recognized as a path.

\emph on
 
\emph default
Note for Windows users: if the path contains spaces, it should be surrounded
 by quotes.
 The trailing backslash should be doubled in order to prevent escaping the
 final quote, for example: 
\emph on
-o 
\begin_inset Quotes sld
\end_inset

F:
\backslash
Projects
\backslash
test3
\backslash
output 1
\backslash

\backslash

\begin_inset Quotes srd
\end_inset


\emph default
 or put after the final quote, for example: 
\emph on
-o 
\begin_inset Quotes sld
\end_inset

F:
\backslash
Projects
\backslash
test3
\backslash
output 1
\begin_inset Quotes srd
\end_inset


\backslash

\emph default
.
 The path using slashes for directory delimiters can be used too, for example:
 
\emph on
-o 
\begin_inset Quotes sld
\end_inset

F:/Projects/test3/output 1/
\begin_inset Quotes srd
\end_inset


\emph default
.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset


\series default
\size large
\emph on
 
\size default
\emph default
All functions in the source file will be compiled as 
\emph on
reentrant
\emph default

\begin_inset LatexCommand \index{reentrant}

\end_inset

, i.e.
 the parameters and local variables will be allocated on the stack
\begin_inset LatexCommand \index{stack}

\end_inset

.
 See section 
\begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}

\end_inset

 Parameters and Local Variables for more details.
 If this option is used all source files in the project should be compiled
 with this option.
 It automatically implies -
\series bold

\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series default
-int-long-reent and -
\series bold

\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series default
-float-reent.
 
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves
\begin_inset LatexCommand \index{-\/-callee-saves}

\end_inset

 
\begin_inset LatexCommand \label{lyx:--callee-saves-function1[,function2][,function3]...}

\end_inset

function1[,function2][,function3]....

\series default
 The compiler by default uses a caller saves convention for register saving
 across function calls, however this can cause unnecessary register pushing
 and popping when calling small functions from larger functions.
 This option can be used to switch the register saving convention for the
 function names specified.
 The compiler will not save registers when calling these functions, no extra
 code will be generated at the entry and exit (function prologue
\series bold

\begin_inset LatexCommand \index{function prologue}

\end_inset


\series default
 and epilogue
\series bold

\begin_inset LatexCommand \index{function epilogue}

\end_inset


\series default
) for these functions to save and restore the registers used by these functions,
 this can SUBSTANTIALLY reduce code and improve run time performance of
 the generated code.
 In the future the compiler (with inter procedural analysis) will be able
 to determine the appropriate scheme to use for each function call.
 DO NOT use this option for built-in functions such as _mulint..., if this
 option is used for a library function the appropriate library function
 needs to be recompiled with the same option.
 If the project consists of multiple source files then all the source file
 should be compiled with the same -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves option string.
 Also see #pragma\InsetSpace ~
callee_saves 
\begin_inset LatexCommand \index{\#pragma callee\_saves}

\end_inset

 
\begin_inset LatexCommand \vpageref{ite:callee_saves-function1[,function2[,function3...]]--}

\end_inset

.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-all-callee-saves
\begin_inset LatexCommand \index{-\/-all-callee-saves}

\end_inset

 
\series default
Function of
\series bold
 
\series default
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves will be applied to all functions by default.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug
\begin_inset LatexCommand \index{-\/-debug}

\end_inset


\bar under
 
\series default
\bar default
When this option is used the compiler will generate debug information.
 The debug information collected in a file with .cdb extension can be used
 with the SDCDB.
 For more information see documentation for SDCDB.
 Another file with no extension contains debug information in AOMF or AOMF51
\begin_inset LatexCommand \index{AOMF, AOMF51}

\end_inset

 format which is commonly used by third party tools.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-S
\begin_inset LatexCommand \index{-S}

\end_inset


\size large
\bar under
 
\series default
\size default
\bar default
Stop after the stage of compilation proper; do not assemble.
 The output is an assembler code file for the input file specified.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-int-long-reent
\begin_inset LatexCommand \index{-\/-int-long-reent}

\end_inset


\series default
 Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
 Note by default these libraries are compiled as non-reentrant.
 See section Installation for more details.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-cyclomatic
\begin_inset LatexCommand \index{-\/-cyclomatic}

\end_inset


\bar under
 
\series default
\bar default
This option will cause the compiler to generate an information message for
 each function in the source file.
 The message contains some 
\emph on
important
\emph default
 information about the function.
 The number of edges and nodes the compiler detected in the control flow
 graph of the function, and most importantly the 
\emph on
cyclomatic complexity
\begin_inset LatexCommand \index{Cyclomatic complexity}

\end_inset


\emph default
 see section on Cyclomatic Complexity for more details.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-float-reent
\begin_inset LatexCommand \index{-\/-float-reent}

\end_inset


\series default
 Floating point library is compiled as reentrant
\begin_inset LatexCommand \index{reentrant}

\end_inset

.
 See section Installation for more details.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-funsigned-char
\begin_inset LatexCommand \index{-\/-funsigned-char}

\end_inset


\series default
 The default signedness for every type is
\family typewriter
 signed
\family default
.
 In some embedded environments the default signedness of
\family typewriter
 char
\family default
 is
\family typewriter
 unsigned
\family default
.
 To set the signess for characters to unsigned, use the option -
\series bold

\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series default
-funsigned-char.
 If this option is set and no signedness keyword (unsigned/signed) is given,
 a char will be signed.
 All other types are unaffected.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-main-return
\begin_inset LatexCommand \index{-\/-main-return}

\end_inset


\series default
 This option can be used if the code generated is called by a monitor program
 or if the main routine includes an endless loop.
 This option results in slightly smaller code and saves two bytes of stack
 space.
 The return from the 'main'
\begin_inset LatexCommand \index{main return}

\end_inset

 function will return to the function calling main.
 The default setting is to lock up i.e.
 generate a '
\family typewriter
sjmp .
\family default
'.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nostdinc
\begin_inset LatexCommand \index{-\/-nostdinc}

\end_inset


\series default
 This will prevent the compiler from passing on the default include path
 to the preprocessor.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nostdlib
\begin_inset LatexCommand \index{-\/-nostdlib}

\end_inset


\series default
 This will prevent the compiler from passing on the default library
\begin_inset LatexCommand \index{Libraries}

\end_inset

 path to the linker.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-verbose
\begin_inset LatexCommand \index{-\/-verbose}

\end_inset


\series default
 Shows the various actions the compiler is performing.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-V
\begin_inset LatexCommand \index{-V}

\end_inset


\series default
 Shows the actual commands the compiler is executing.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-c-code-in-asm
\begin_inset LatexCommand \index{-\/-no-c-code-in-asm}

\end_inset


\series default
 Hides your ugly and inefficient c-code from the asm file, so you can always
 blame the compiler :)
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-fverbose-asm
\begin_inset LatexCommand \index{-\/-no-gen-comments}

\end_inset


\series default
 Include code generator and peep-hole comments in the generated asm files.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-peep-comments
\begin_inset LatexCommand \index{-\/-no-peep-comments}

\end_inset


\series default
 Don't include peep-hole comments in the generated asm files even if -
\series bold

\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series default
-fverbose-asm option is specified.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-i-code-in-asm
\begin_inset LatexCommand \index{-\/-i-code-in-asm}

\end_inset


\series default
 Include i-codes in the asm file.
 Sounds like noise but is most helpful for debugging the compiler itself.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-less-pedantic
\begin_inset LatexCommand \index{pedantic}

\end_inset


\begin_inset LatexCommand \index{-\/-less-pedantic}

\end_inset


\series default

\begin_inset LatexCommand \label{lyx:--less-pedantic}

\end_inset

 Disable some of the more pedantic warnings
\begin_inset LatexCommand \index{Warnings}

\end_inset

.
 For more details, see the less_pedantic pragma 
\begin_inset LatexCommand \vpageref{ite:less_pedantic}

\end_inset

.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-disable-warning\InsetSpace ~
<nnnn>
\begin_inset LatexCommand \index{-\/-disable-warning}

\end_inset


\series default
 Disable specific warning with number <nnnn>.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-Werror
\begin_inset LatexCommand \index{-\/-Werror}

\end_inset


\series default
 Treat all warnings as errors.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-print-search-dirs
\begin_inset LatexCommand \index{-\/-print-search-dirs}

\end_inset


\series default
 Display the directories in the compiler's search path
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-vc
\begin_inset LatexCommand \index{-\/-vc}

\end_inset


\series default
 Display errors and warnings using MSVC style, so you can use SDCC with
 the visual studio IDE
\begin_inset LatexCommand \index{IDE}

\end_inset

.
 With SDCC both offering a GCC-like (the default) and a MSVC-like
\begin_inset LatexCommand \index{MSVC output style}

\end_inset

 output style, integration into most programming editors should be straightforwa
rd.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-use-stdout
\begin_inset LatexCommand \index{-\/-use-stdout}

\end_inset


\series default
 Send errors and warnings to stdout instead of stderr.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-Wa\InsetSpace ~
asmOption[,asmOption]
\series default

\begin_inset LatexCommand \index{-Wa asmOption[,asmOption]}

\end_inset

...
 Pass the asmOption to the assembler
\begin_inset LatexCommand \index{Options assembler}

\end_inset


\begin_inset LatexCommand \index{Assembler options}

\end_inset

.
 See file sdcc/as/doc/asxhtm.html for assembler options.cd
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-sdcc89
\begin_inset LatexCommand \index{-\/-std-sdcc89}

\end_inset


\series default
 Generally follow the C89 standard, but allow SDCC features that conflict
 with the standard (default).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c89
\begin_inset LatexCommand \index{-\/-std-c89}

\end_inset


\series default
 Follow the C89 standard and disable SDCC features that conflict with the
 standard.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-sdcc99
\begin_inset LatexCommand \index{-\/-std-sdcc99}

\end_inset


\series default
 Generally follow the C99 standard, but allow SDCC features that conflict
 with the standard (incomplete support).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c99
\begin_inset LatexCommand \index{-\/-std-sdcc99}

\end_inset


\series default
 Follow the C99 standard and disable SDCC features that conflict with the
 standard (incomplete support).
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-codeseg
\series default

\begin_inset LatexCommand \index{-\/-codeseg <Value>}

\end_inset

\begin_inset LatexCommand \label{lyx:-codeseg}

\end_inset

\InsetSpace ~
<Name> The name to be used for the code
\begin_inset LatexCommand \index{code}

\end_inset

 segment, default CSEG.
 This is useful if you need to tell the compiler to put the code in a special
 segment so you can later on tell the linker to put this segment in a special
 place in memory.
 Can be used for instance when using bank switching to put the code in a
 bank.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-constseg
\series default

\begin_inset LatexCommand \index{-\/-constseg <Value>}

\end_inset

\InsetSpace ~
<Name> The name to be used for the const
\begin_inset LatexCommand \index{const}

\end_inset

 segment, default CONST.
 This is useful if you need to tell the compiler to put the const data in
 a special segment so you can later on tell the linker to put this segment
 in a special place in memory.
 Can be used for instance when using bank switching to put the const data
 in a bank.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-fdollars-in-identifiers
\begin_inset LatexCommand \index{-\/-fdollars-in-identifiers}

\end_inset


\series default
 Permit '$' as an identifier character.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-more-pedantic
\series default

\begin_inset LatexCommand \index{-\/-more-pedantic}

\end_inset


\begin_inset LatexCommand \index{pedantic}

\end_inset

 Actually this is 
\series bold
\emph on
not
\series default
\emph default
 a SDCC compiler option but if you want 
\emph on
more
\emph default
 warnings you can use a separate tool dedicated to syntax checking like
 splint
\begin_inset LatexCommand \label{lyx:more-pedantic-SPLINT}

\end_inset


\begin_inset LatexCommand \index{lint (syntax checking tool)}

\end_inset

 
\begin_inset LatexCommand \url{http://www.splint.org}

\end_inset

.
 To make your source files parseable by splint you will have to include
 
\family sans
lint.h
\family default

\begin_inset LatexCommand \index{splint (syntax checking tool)}

\end_inset

 in your source file and add brackets around extended keywords (like 
\family sans

\begin_inset Quotes sld
\end_inset

__at\InsetSpace ~

\series bold
(
\series default
0xab
\series bold
)
\series default

\begin_inset Quotes srd
\end_inset


\family default
 and 
\family sans

\begin_inset Quotes sld
\end_inset

__interrupt\InsetSpace ~
(2)
\begin_inset Quotes srd
\end_inset


\family default
).
 
\newline
Splint has an excellent on line manual at 
\begin_inset LatexCommand \url{http://www.splint.org/manual/}

\end_inset

 and it's capabilities go beyond pure syntax checking.
 You'll need to tell splint the location of SDCC's include files so a typical
 command line could look like this: 
\newline

\family sans
splint\InsetSpace ~
-I\InsetSpace ~
/usr/local/share/sdcc/include/mcs51/\InsetSpace ~
\InsetSpace ~
myprogram.c
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-short-is-8bits
\series default

\begin_inset LatexCommand \index{-\/-short-is-8bits}

\end_inset


\begin_inset LatexCommand \label{lyx:--short-is-8bits}

\end_inset

 Treat short as 8-bit (for backward compatibility with older versions of
 compiler - see section 
\begin_inset LatexCommand \ref{sec:Compatibility-with-previous}

\end_inset

)
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Intermediate Dump Options
\begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}

\end_inset


\begin_inset LatexCommand \index{Options intermediate dump}

\end_inset


\begin_inset LatexCommand \index{Intermediate dump options}

\end_inset


\end_layout

\begin_layout Standard
The following options are provided for the purpose of retargetting and debugging
 the compiler.
 They provide a means to dump the intermediate code (iCode
\begin_inset LatexCommand \index{iCode}

\end_inset

) generated by the compiler in human readable form at various stages of
 the compilation process.
 More on iCodes see chapter 
\begin_inset LatexCommand \ref{sub:The-anatomy-of}

\end_inset

 
\begin_inset Quotes srd
\end_inset

The anatomy of the compiler
\begin_inset Quotes srd
\end_inset

.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpraw
\begin_inset LatexCommand \index{-\/-dumpraw}

\end_inset


\series default
 This option will cause the compiler to dump the intermediate code into
 a file of named 
\emph on
<source filename>.dumpraw
\emph default
 just after the intermediate code has been generated for a function, i.e.
 before any optimizations are done.
 The basic blocks
\begin_inset LatexCommand \index{Basic blocks}

\end_inset

 at this stage ordered in the depth first number, so they may not be in
 sequence of execution.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpgcse
\begin_inset LatexCommand \index{-\/-dumpgcse}

\end_inset


\series default
 Will create a dump of iCodes, after global subexpression elimination
\begin_inset LatexCommand \index{Global subexpression elimination}

\end_inset

, into a file named 
\emph on
<source filename>.dumpgcse.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpdeadcode
\begin_inset LatexCommand \index{-\/-dumpdeadcode}

\end_inset


\series default
 Will create a dump of iCodes, after deadcode elimination
\begin_inset LatexCommand \index{Dead-code elimination}

\end_inset

, into a file named 
\emph on
<source filename>.dumpdeadcode.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumploop
\begin_inset LatexCommand \index{-\/-dumploop}

\end_inset


\series default
\size large
 
\size default
Will create a dump of iCodes, after loop optimizations
\begin_inset LatexCommand \index{Loop optimization}

\end_inset

, into a file named 
\emph on
<source filename>.dumploop.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumprange
\begin_inset LatexCommand \index{-\/-dumprange}

\end_inset


\series default
\size large
 
\size default
Will create a dump of iCodes, after live range analysis
\begin_inset LatexCommand \index{Live range analysis}

\end_inset

, into a file named 
\emph on
<source filename>.dumprange.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumlrange
\begin_inset LatexCommand \index{-\/-dumlrange}

\end_inset


\series default
 Will dump the life ranges
\begin_inset LatexCommand \index{Live range analysis}

\end_inset

 for all symbols.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpregassign
\begin_inset LatexCommand \index{-\/-dumpregassign}

\end_inset


\bar under
 
\series default
\bar default
Will create a dump of iCodes, after register assignment
\begin_inset LatexCommand \index{Register assignment}

\end_inset

, into a file named 
\emph on
<source filename>.dumprassgn.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumplrange
\begin_inset LatexCommand \index{-\/-dumplrange}

\end_inset


\series default
 Will create a dump of the live ranges of iTemp's
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpall
\begin_inset LatexCommand \index{-\/-dumpall}

\end_inset


\size large
\bar under
 
\series default
\size default
\bar default
Will cause all the above mentioned dumps to be created.
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Redirecting output on Windows Shells
\end_layout

\begin_layout Standard
By default SDCC writes its error messages to 
\begin_inset Quotes sld
\end_inset

standard error
\begin_inset Quotes srd
\end_inset

.
 To force all messages to 
\begin_inset Quotes sld
\end_inset

standard output
\begin_inset Quotes srd
\end_inset

 use 
\series bold
-
\series default
\emph on

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series bold
\emph default
-
\series default
use-stdout
\begin_inset LatexCommand \index{-\/-use-stdout}

\end_inset

.
 Additionally, if you happen to have visual studio installed in your windows
 machine, you can use it to compile your sources using a custom build and
 the SDCC -
\emph on

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\emph default
-vc
\begin_inset LatexCommand \index{-\/-vc}

\end_inset

 option.
 Something like this should work:
\newline

\newline

\series bold
c:
\backslash
sdcc
\backslash
bin
\backslash
sdcc.exe -
\series default
\emph on

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series bold
\emph default
-vc -
\series default
\emph on

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series bold
\emph default
-model-large -c $(InputPath)
\series default

\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Environment variables
\begin_inset LatexCommand \index{Environment variables}

\end_inset


\end_layout

\begin_layout Standard
SDCC recognizes the following environment variables:
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
SDCC_LEAVE_SIGNALS
\begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}

\end_inset


\series default
 SDCC installs a signal handler
\begin_inset LatexCommand \index{signal handler}

\end_inset

 to be able to delete temporary files after an user break (^C) or an exception.
 If this environment variable is set, SDCC won't install the signal handler
 in order to be able to debug SDCC.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
TMP,\InsetSpace ~
TEMP,\InsetSpace ~
TMPDIR
\begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}

\end_inset


\series default
 Path, where temporary files will be created.
 The order of the variables is the search order.
 In a standard *nix environment these variables are not set, and there's
 no need to set them.
 On Windows it's recommended to set one of them.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
SDCC_HOME
\begin_inset LatexCommand \index{SDCC\_HOME}

\end_inset


\series default
 Path, see section 
\begin_inset LatexCommand \ref{sub:Install-paths}

\end_inset

\InsetSpace ~

\begin_inset Quotes sld
\end_inset

 Install Paths
\begin_inset Quotes srd
\end_inset

.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
SDCC_INCLUDE
\begin_inset LatexCommand \index{SDCC\_INCLUDE}

\end_inset


\series default
 Path, see section 
\begin_inset LatexCommand \ref{sub:Search-Paths}

\end_inset

\InsetSpace ~

\begin_inset Quotes sld
\end_inset

Search Paths
\begin_inset Quotes srd
\end_inset

.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series bold
SDCC_LIB
\begin_inset LatexCommand \index{SDCC\_LIB}

\end_inset


\series default
 Path, see section 
\begin_inset LatexCommand \ref{sub:Search-Paths}

\end_inset

\InsetSpace ~

\begin_inset Quotes sld
\end_inset

Search Paths
\begin_inset Quotes srd
\end_inset

..
\end_layout

\begin_layout Standard
There are some more environment variables recognized by SDCC, but these
 are solely used for debugging purposes.
 They can change or disappear very quickly, and will never be documented.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Storage Class Language Extensions
\end_layout

\begin_layout Subsection
MCS51/DS390 Storage Class
\begin_inset LatexCommand \index{Storage class}

\end_inset

 Language Extensions
\end_layout

\begin_layout Standard
In addition to the ANSI storage classes SDCC allows the following MCS51
 specific storage classes:
\end_layout

\begin_layout Subsubsection
data
\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}

\end_inset

 / near
\begin_inset LatexCommand \index{near (storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_near (storage class)}

\end_inset


\end_layout

\begin_layout Standard
This is the 
\series bold
default
\series default
 storage class for the Small Memory model (
\emph on
data
\emph default
 and 
\emph on
near
\emph default
 or the more ANSI-C compliant forms 
\emph on
__data
\emph default
 and 
\emph on
__near
\emph default
 can be used synonymously).
 Variables declared with this storage class will be allocated in the directly
 addressable portion of the internal RAM of a 8051, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
__data unsigned char test_data;
\end_layout

\begin_layout Standard
Writing 0x01 to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
75*00 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
_test_data,#0x01
\end_layout

\begin_layout Subsubsection
xdata
\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}

\end_inset

 / far
\begin_inset LatexCommand \index{far (storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_far (storage class)}

\end_inset


\end_layout

\begin_layout Standard
Variables declared with this storage class will be placed in the external
 RAM.
 This is the 
\series bold
default
\series default
 storage class for the Large Memory model, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
__xdata unsigned char test_xdata;
\end_layout

\begin_layout Standard
Writing 0x01 to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
90s00r00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
dptr,#_test_xdata 
\newline
74\InsetSpace ~
01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
a,#0x01 
\newline
F0\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movx\InsetSpace ~
@dptr,a 
\end_layout

\begin_layout Subsubsection
idata
\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}

\end_inset


\end_layout

\begin_layout Standard
Variables declared with this storage class will be allocated into the indirectly
 addressable portion of the internal ram of a 8051, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
__idata unsigned char test_idata;
\end_layout

\begin_layout Standard
Writing 0x01 to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
78r00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
r0,#_test_idata
\newline
76\InsetSpace ~
01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
@r0,#0x01
\end_layout

\begin_layout Standard
Please note, the first 128 byte of idata physically access the same RAM
 as the data memory.
 The original 8051 had 128 byte idata memory, nowadays most devices have
 256 byte idata memory.
 The stack
\begin_inset LatexCommand \index{stack}

\end_inset

 is located in idata memory.
\end_layout

\begin_layout Subsubsection
pdata
\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_pdata (mcs51, ds390 storage class)}

\end_inset


\end_layout

\begin_layout Standard
Paged xdata access is just as straightforward as using the other addressing
 modes of a 8051.
 It is typically located at the start of xdata and has a maximum size of
 256 bytes.
 The following example writes 0x01 to the pdata variable.
 Please note, pdata access physically accesses xdata memory.
 The high byte of the address is determined by port P2 
\begin_inset LatexCommand \index{P2 (mcs51 sfr)}

\end_inset

(or in case of some 8051 variants by a separate Special Function Register,
 see section 
\begin_inset LatexCommand \ref{sub:MCS51-variants}

\end_inset

).
 This is the 
\series bold
default
\series default
 storage class for the Medium Memory model, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
__pdata unsigned char test_pdata;
\end_layout

\begin_layout Standard
Writing 0x01 to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
78r00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r0,#_test_pdata
\newline
74 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov a,#0x01 
\newline
F2\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movx @r0,a
\end_layout

\begin_layout Standard
If the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack
\begin_inset LatexCommand \index{-\/-xstack}

\end_inset

 option is used the pdata memory area is followed by the xstack memory area
 and the sum of their sizes is limited to 256 bytes.
\end_layout

\begin_layout Subsubsection
code
\begin_inset LatexCommand \index{code}

\end_inset


\begin_inset LatexCommand \index{\_\_code}

\end_inset


\end_layout

\begin_layout Standard
'Variables' declared with this storage class will be placed in the code
 memory:
\end_layout

\begin_layout Verse

\family typewriter
__code unsigned char test_code;
\end_layout

\begin_layout Standard
Read access to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
90s00r6F\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov dptr,#_test_code
\newline
E4\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
clr a
\newline
93\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movc a,@a+dptr 
\end_layout

\begin_layout Standard

\family typewriter
char
\family default
 indexed arrays of characters in code memory can be accessed efficiently:
\end_layout

\begin_layout Verse

\family typewriter
__code char test_array[] = {'c','h','e','a','p'}; 
\end_layout

\begin_layout Standard
Read access to this array using an 8-bit unsigned index generates the assembly
 code:
\end_layout

\begin_layout Verse

\family typewriter
E5*00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov a,_index 
\end_layout

\begin_layout Verse

\family typewriter
90s00r41\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov dptr,#_test_array
\end_layout

\begin_layout Verse

\family typewriter
93\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movc a,@a+dptr 
\end_layout

\begin_layout Subsubsection
bit
\begin_inset LatexCommand \index{bit}

\end_inset


\begin_inset LatexCommand \index{\_\_bit}

\end_inset


\end_layout

\begin_layout Standard
This is a data-type and a storage class specifier.
 When a variable is declared as a bit, it is allocated into the bit addressable
 memory of 8051, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
__bit test_bit;
\end_layout

\begin_layout Standard
Writing 1 to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
D2*00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
setb\InsetSpace ~
_test_bit
\end_layout

\begin_layout Standard
The bit addressable memory consists of 128 bits which are located from 0x20
 to 0x2f in data memory.
 
\newline
Apart from this 8051 specific storage class most architectures support
 ANSI-C bitfields
\begin_inset LatexCommand \index{bitfields}

\end_inset


\begin_inset Foot
status open

\begin_layout Standard
Not really meant as examples, but nevertheless showing what bitfields are
 about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
\end_layout

\end_inset

.
 In accordance with ISO/IEC 9899 bits and bitfields without an explicit
 signed modifier are implemented as unsigned.
\end_layout

\begin_layout Subsubsection
sfr
\begin_inset LatexCommand \index{sfr}

\end_inset


\begin_inset LatexCommand \index{\_\_sfr}

\end_inset

 / sfr16
\begin_inset LatexCommand \index{sfr16}

\end_inset


\begin_inset LatexCommand \index{\_\_sfr16}

\end_inset

 / sfr32
\begin_inset LatexCommand \index{sfr32}

\end_inset


\begin_inset LatexCommand \index{\_\_sfr32}

\end_inset

 / sbit
\begin_inset LatexCommand \index{\_\_sbit}

\end_inset


\begin_inset LatexCommand \index{sbit}

\end_inset


\end_layout

\begin_layout Standard
Like the bit keyword, 
\emph on
sfr / sfr16 / sfr32 / sbit 
\emph default
signify both a data-type and storage class, they are used to describe the
 
\emph on
s
\emph default
pecial 
\emph on
f
\emph default
unction 
\emph on
r
\emph default
egisters and 
\emph on
s
\emph default
pecial 
\emph on
bit
\emph default
 variables of a 8051, eg:
\end_layout

\begin_layout Verse

\family typewriter
__sfr __at
\begin_inset LatexCommand \index{at}

\end_inset


\begin_inset LatexCommand \index{\_\_at}

\end_inset

 (0x80) P0;\InsetSpace ~
 /* special function register P0 at location 0x80 */
\newline

\newline
/* 16 bit
 special function register combination for timer 0
\newline
\InsetSpace ~
\InsetSpace ~
 with the high byte at
 location 0x8C and the low byte at location 0x8A */
\newline
__sfr16 __at (0x8C8A)
 TMR0;
\newline

\newline
__sbit __at
\begin_inset LatexCommand \index{at}

\end_inset


\begin_inset LatexCommand \index{\_\_at}

\end_inset

 (0xd7) CY;\InsetSpace ~
 /* CY (Carry Flag
\begin_inset LatexCommand \index{Flags}

\end_inset


\begin_inset LatexCommand \index{Carry flag}

\end_inset

) */
\end_layout

\begin_layout Standard
Special function registers which are located on an address dividable by
 8 are bit-addressable, an
\emph on
 sbit
\emph default
 addresses a specific bit within these sfr.
\newline
16 Bit and 32 bit special function
 register combinations which require a certain access order are better not
 declared using 
\emph on
sfr16
\emph default
 or 
\emph on
sfr32.

\emph default
 Allthough SDCC usually accesses them Least Significant Byte (LSB) first,
 this is not guaranteed.
\newline

\end_layout

\begin_layout Standard
Please note, if you use a header file which was written for another compiler
 then the sfr / sfr16 / sfr32 / sbit Storage Class extensions will most
 likely be 
\emph on
not 
\emph default
compatible.
 Specifically the syntax 
\family typewriter
\InsetSpace ~
sfr P0 = 0x80;\InsetSpace ~

\family default
 is compiled 
\emph on
without warning
\emph default
 by SDCC to an assignment of 0x80 to a variable called P0 
\family typewriter

\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
\InsetSpace ~
!
\end_layout

\end_inset

.
 
\family default
Nevertheless it is possible to write header files
\begin_inset LatexCommand \index{Header files}

\end_inset


\begin_inset LatexCommand \index{Include files}

\end_inset

 which can be shared among different compilers (see section 
\begin_inset LatexCommand \ref{sec:Porting-code-to-other-compilers}

\end_inset

).
 
\end_layout

\begin_layout Subsubsection
Pointers
\begin_inset LatexCommand \index{Pointer}

\end_inset

 to MCS51/DS390 specific memory spaces
\end_layout

\begin_layout Standard
SDCC allows (via language extensions) pointers to explicitly point to any
 of the memory spaces
\begin_inset LatexCommand \index{Memory model}

\end_inset

 of the 8051.
 In addition to the explicit pointers, the compiler uses (by default) generic
 pointers which can be used to point to any of the memory spaces.
\newline

\newline
Pointer
 declaration examples:
\end_layout

\begin_layout Verse

\family typewriter
/* pointer physically in internal ram pointing to object in external ram
 */ 
\newline
__xdata unsigned char * __data p;
\newline

\newline
/* pointer physically in external ram
 pointing to object in internal ram */ 
\newline
__data unsigned char * __xdata p;
\newline

\newline
/*
 pointer physically in code rom pointing to data in xdata space */ 
\newline
__xdata
 unsigned char * __code p;
\newline

\newline
/* pointer physically in code space pointing to
 data in code space */ 
\newline
__code unsigned char * __code p;
\newline

\newline
/* generic pointer
 physically located in xdata space */
\newline
unsigned char * __xdata p;
\newline

\newline
/* generic
 pointer physically located in default memory space */
\newline
unsigned char * p;
\newline

\newline
/*
 the following is a function pointer
\begin_inset LatexCommand \index{function pointer}

\end_inset

 physically located in data space */
\newline
char (* __data fp)(void);
\end_layout

\begin_layout Standard
Well you get the idea.
 
\newline

\newline
All unqualified pointers are treated as 3-byte (4-byte for the ds390) 
\emph on
generic
\emph default
 pointers.
 
\size small

\newline

\newline

\size default
The highest order byte of the 
\emph on
generic
\emph default
 pointers contains the data space information.
 Assembler support routines are called whenever data is stored or retrieved
 using 
\emph on
generic
\emph default
 pointers.
 These are useful for developing reusable library
\begin_inset LatexCommand \index{Libraries}

\end_inset

 routines.
 Explicitly specifying the pointer
\begin_inset LatexCommand \index{pointer}

\end_inset

 type will generate the most efficient code.
\end_layout

\begin_layout Subsubsection
Notes on MCS51 memory
\begin_inset LatexCommand \index{MCS51 memory}

\end_inset

 layout
\end_layout

\begin_layout Standard
The 8051 family of microcontrollers have a minimum of 128 bytes of internal
 RAM memory which is structured as follows:
\newline

\newline
- Bytes 00-1F - 32 bytes to hold
 up to 4 banks of the registers R0 to R7, 
\newline
- Bytes 20-2F - 16 bytes to hold
 128 bit
\begin_inset LatexCommand \index{bit}

\end_inset

 variables and, 
\newline
- Bytes 30-7F - 80 bytes for general purpose use.
\newline

\end_layout

\begin_layout Standard
Additionally some members of the MCS51 family may have up to 128 bytes of
 additional, indirectly addressable, internal RAM memory (
\emph on
idata
\emph default

\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}

\end_inset

).
 Furthermore, some chips may have some built in external memory (
\emph on
xdata
\emph default

\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}

\end_inset

) which should not be confused with the internal, directly addressable RAM
 memory (
\emph on
data
\emph default

\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}

\end_inset

).
 Sometimes this built in 
\emph on
xdata
\emph default
 memory has to be activated before using it (you can probably find this
 information on the datasheet of the microcontroller your are using, see
 also section 
\begin_inset LatexCommand \ref{sub:Startup-Code}

\end_inset

\InsetSpace ~
Startup-Code).
\end_layout

\begin_layout Standard
Normally SDCC will only use the first bank
\begin_inset LatexCommand \index{register bank (mcs51, ds390)}

\end_inset

 of registers (register bank 0), but it is possible to specify that other
 banks of registers (keyword 
\emph on
using
\emph default
 
\emph on

\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}

\end_inset


\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}

\end_inset


\emph default
) should be used for example in interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset


\begin_inset LatexCommand \index{\_\_interrupt}

\end_inset

 routines.
 By default, the compiler will place the stack after the last byte of allocated
 memory for variables.
 For example, if the first 2 banks of registers are used, and only four
 bytes are used for 
\emph on
data
\emph default
 variables, it will position the base of the internal stack at address 20
 (0x14).
 This implies that as the stack
\begin_inset LatexCommand \index{stack}

\end_inset

 grows, it will use up the remaining register banks, and the 16 bytes used
 by the 128 bit variables, and 80 bytes for general purpose use.
 If any bit variables are used, the data variables will be placed in unused
 register banks and after the byte holding the last bit variable.
 For example, if register banks 0 and 1 are used, and there are 9 bit variables
 (two bytes used), 
\emph on
data
\emph default
 variables will be placed starting from address 0x10 to 0x20 and continue
 at address 0x22.
 You can also use -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-data-loc
\begin_inset LatexCommand \index{-\/-data-loc <Value>}

\end_inset

 to specify the start address of the 
\emph on
data
\emph default
 and -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-iram-size
\begin_inset LatexCommand \index{-\/-iram-size <Value>}

\end_inset

 to specify the size of the total internal RAM (
\emph on
data
\emph default
+
\emph on
idata
\emph default
).
 
\newline

\end_layout

\begin_layout Standard
By default the 8051 linker will place the stack after the last byte of (i)data
 variables.
 Option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-loc
\begin_inset LatexCommand \index{-\/-stack-loc <Value>}

\end_inset

 allows you to specify the start of the stack, i.e.
 you could start it after any data in the general purpose area.
 If your microcontroller has additional indirectly addressable internal
 RAM (
\emph on
idata
\emph default
) you can place the stack on it.
 You may also need to use -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xdata-loc
\begin_inset LatexCommand \index{-\/-xdata-loc<Value>}

\end_inset

 to set the start address of the external RAM (
\emph on
xdata
\emph default
) and -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xram-size
\begin_inset LatexCommand \index{-\/-xram-size <Value>}

\end_inset

 to specify its size.
 Same goes for the code memory, using -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-code-loc
\begin_inset LatexCommand \index{-\/-code-loc <Value>}

\end_inset

 and -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-code-size
\begin_inset LatexCommand \index{-\/-code-size <Value>}

\end_inset

.
 If in doubt, don't specify any options and see if the resulting memory
 layout is appropriate, then you can adjust it.
\end_layout

\begin_layout Standard
The linker generates two files with memory allocation information.
 The first, with extension .map
\begin_inset LatexCommand \index{<file>.map}

\end_inset

 shows all the variables and segments.
 The second with extension .mem
\begin_inset LatexCommand \index{<file>.mem}

\end_inset

 shows the final memory layout.
 The linker will complain either if memory segments overlap, there is not
 enough memory, or there is not enough space for stack.
 If you get any linking warnings and/or errors related to stack or segments
 allocation, take a look at either the .map or .mem files to find out what
 the problem is.
 The .mem file may even suggest a solution to the problem.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Z80/Z180 Storage Class
\begin_inset LatexCommand \index{Z80!Storage class}

\end_inset

 Language Extensions
\end_layout

\begin_layout Subsubsection
sfr
\begin_inset LatexCommand \index{sfr}

\end_inset


\begin_inset LatexCommand \index{\_\_sfr}

\end_inset

 (in/out to 8-bit addresses)
\end_layout

\begin_layout Standard
The Z80
\begin_inset LatexCommand \index{Z80}

\end_inset

 family has separate address spaces for memory and 
\emph on
i
\emph default
nput/
\emph on
o
\emph default
utput memory.
 I/O memory
\begin_inset LatexCommand \index{I/O memory (Z80, Z180)}

\end_inset


\begin_inset LatexCommand \index{Z80!I/O memory}

\end_inset


\begin_inset LatexCommand \index{Z180!I/O memory}

\end_inset

 is accessed with special instructions, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
sfr at 0x78 IoPort;\InsetSpace ~
\InsetSpace ~
/* define a var in I/O space at 78h called IoPort */
 
\end_layout

\begin_layout Standard
Writing 0x01 to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
3E 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ld a,#0x01
\newline
D3 78\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
out (_IoPort),a 
\end_layout

\begin_layout Subsubsection
banked sfr
\begin_inset LatexCommand \index{sfr}

\end_inset


\begin_inset LatexCommand \index{\_\_sfr}

\end_inset

 (in/out to 16-bit addresses)
\end_layout

\begin_layout Standard
The keyword 
\emph on
banked
\emph default
 is used to support 16 bit addresses in I/O memory e.g.:
\end_layout

\begin_layout Verse

\family typewriter
sfr banked at
\begin_inset LatexCommand \index{at}

\end_inset


\begin_inset LatexCommand \index{\_\_at}

\end_inset

 0x123 IoPort; 
\end_layout

\begin_layout Standard
Writing 0x01 to this variable generates the assembly code:
\end_layout

\begin_layout Verse

\family typewriter
01 23 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ld bc,#_IoPort
\newline
3E 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ld a,#0x01 
\newline
ED 79\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
out (c),a 
\end_layout

\begin_layout Subsubsection
sfr
\begin_inset LatexCommand \index{sfr}

\end_inset


\begin_inset LatexCommand \index{\_\_sfr}

\end_inset

 (in0/out0 to 8 bit addresses on Z180
\begin_inset LatexCommand \index{Z180}

\end_inset

/HD64180
\begin_inset LatexCommand \index{HD64180 (see Z180)}

\end_inset

)
\end_layout

\begin_layout Standard
The compiler option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-portmode
\begin_inset LatexCommand \index{Z180!Options!-\/-portmode}

\end_inset

=180 (80) and a compiler #pragma\InsetSpace ~
portmode
\begin_inset LatexCommand \index{Z180!Pragmas!\#pragma portmode}

\end_inset

 z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
ns 
\family typewriter
in0/out0
\family default
 instead of 
\family typewriter
in/out
\family default
.
 If you include the file z180.h this will be set automatically.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
HC08 Storage Class
\begin_inset LatexCommand \index{HC08!Storage class}

\end_inset

 Language Extensions
\end_layout

\begin_layout Subsubsection
data
\begin_inset LatexCommand \index{data (hc08 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_data (hc08 storage class)}

\end_inset

 
\end_layout

\begin_layout Standard
The data storage class declares a variable that resides in the first 256
 bytes of memory (the direct page).
 The HC08
\begin_inset LatexCommand \index{HC08}

\end_inset

 is most efficient at accessing variables (especially pointers) stored here.
\end_layout

\begin_layout Subsubsection
xdata
\begin_inset LatexCommand \index{xdata (hc08 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_xdata (hc08 storage class)}

\end_inset

 
\end_layout

\begin_layout Standard
The xdata storage class declares a variable that can reside anywhere in
 memory.
 This is the default if no storage class is specified.
 
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Absolute Addressing
\begin_inset LatexCommand \index{Absolute addressing}

\end_inset


\end_layout

\begin_layout Standard
Data items can be assigned an absolute address with the 
\emph on
at
\begin_inset LatexCommand \index{at}

\end_inset


\begin_inset LatexCommand \index{\_\_at}

\end_inset

 <address>
\emph default
 keyword, in addition to a storage class, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
xdata
\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}

\end_inset

 at
\begin_inset LatexCommand \index{at}

\end_inset


\begin_inset LatexCommand \index{\_\_at}

\end_inset

 0x7ffe unsigned int chksum;
\end_layout

\begin_layout Standard
or, better conforming to ISO/IEC 9899 C:
\end_layout

\begin_layout Verse

\family typewriter
__xdata __at (0x7ffe) unsigned int chksum;
\end_layout

\begin_layout Standard
In the above example the variable chksum will be located at 0x7ffe and 0x7fff
 of the external ram.
 The compiler does 
\emph on
not
\emph default
 reserve any space for variables declared in this way
\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
\InsetSpace ~
!
\end_layout

\end_inset

 (they are implemented with an equate in the assembler).
 Thus it is left to the programmer to make sure there are no overlaps with
 other variables that are declared without the absolute address.
 The assembler listing file (.lst
\begin_inset LatexCommand \index{<file>.lst}

\end_inset

) and the linker output files (.rst
\begin_inset LatexCommand \index{<file>.rst}

\end_inset

) and (.map
\begin_inset LatexCommand \index{<file>.map}

\end_inset

) are good places to look for such overlaps.
\end_layout

\begin_layout Standard
If however you provide an initializer
\begin_inset LatexCommand \index{Variable initialization}

\end_inset

 actual memory allocation will take place and overlaps will be detected
 by the linker.
 E.g.:
\end_layout

\begin_layout Verse

\family typewriter
__code __at (0x7ff0) char Id[5] = 
\begin_inset Quotes sld
\end_inset

SDCC
\begin_inset Quotes srd
\end_inset

;
\end_layout

\begin_layout Standard
In the above example the variable Id will be located from 0x7ff0 to 0x7ff4
 in code memory.
\end_layout

\begin_layout Standard
In case of memory mapped I/O devices the keyword 
\emph on
volatile
\emph default
 has to be used to tell the compiler that accesses might not be removed:
\end_layout

\begin_layout Verse

\family typewriter
volatile
\begin_inset LatexCommand \index{volatile}

\end_inset

 __xdata
\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}

\end_inset

 __at
\begin_inset LatexCommand \index{at}

\end_inset

 (0x8000) unsigned char PORTA_8255;
\end_layout

\begin_layout Standard
For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
r) array
\family typewriter
\size footnotesize

\begin_inset LatexCommand \index{Aligned array}

\end_inset


\family default
\size default
 starts at a block (256 byte) boundary
\begin_inset LatexCommand \index{block boundary}

\end_inset

 (section 
\begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}

\end_inset

 has an example).
\newline
Absolute addresses can be specified for variables in all
 storage classes, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
__bit
\begin_inset LatexCommand \index{bit}

\end_inset

 __at
\begin_inset LatexCommand \index{at}

\end_inset

 (0x02) bvar;
\end_layout

\begin_layout Standard
The above example will allocate the variable at offset 0x02 in the bit-addressab
le space.
 There is no real advantage to assigning absolute addresses to variables
 in this manner, unless you want strict control over all the variables allocated.
 One possible use would be to write hardware portable code.
 For example, if you have a routine that uses one or more of the microcontroller
 I/O pins, and such pins are different for two different hardwares, you
 can declare the I/O pins in your routine using:
\end_layout

\begin_layout Verse

\family typewriter
extern volatile
\begin_inset LatexCommand \index{volatile}

\end_inset

 __bit MOSI;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* master out, slave in */
\newline
extern volatile __bit MISO;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* master
 in, slave out */
\newline
extern volatile __bit MCLK;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* master clock */
\newline

\newline
/* Input and
 Output of a byte on a 3-wire serial bus.
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
If needed adapt polarity of clock,
 polarity of data and bit order
\newline
\InsetSpace ~
*/
\newline
unsigned char spi_io(unsigned char out_byte)
 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
unsigned char i=8;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
do { 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
MOSI = out_byte & 0x80; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
out_byte <<= 1;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
MCLK =
 1; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* _asm nop _endasm; */\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* for slow peripherals */
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
if(MISO) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
out_byte +=
 1; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
MCLK = 0; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
} while(--i);
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
return out_byte; 
\newline
}
\end_layout

\begin_layout Standard
Then, someplace in the code for the first hardware you would use
\end_layout

\begin_layout Verse

\family typewriter
__bit __at
\begin_inset LatexCommand \index{at}

\end_inset


\begin_inset LatexCommand \index{\_\_at}

\end_inset

 (0x80) MOSI;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* I/O port 0, bit 0 */
\newline
__bit __at (0x81) MISO;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* I/O port 0,
 bit 1 */
\newline
__bit __at (0x82) MCLK;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* I/O port 0, bit 2 */
\end_layout

\begin_layout Standard
Similarly, for the second hardware you would use
\end_layout

\begin_layout Verse

\family typewriter
__bit __at (0x83) MOSI;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* I/O port 0, bit 3 */
\newline
__bit __at (0x91) MISO;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/*
 I/O port 1, bit 1 */
\newline
__bit
\begin_inset LatexCommand \index{bit}

\end_inset

 __at (0x92) MCLK;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* I/O port 1, bit 2 */
\end_layout

\begin_layout Standard
and you can use the same hardware dependent routine without changes, as
 for example in a library.
 This is somehow similar to sbit, but only one absolute address has to be
 specified in the whole project.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Parameters
\begin_inset LatexCommand \index{Parameters}

\end_inset


\begin_inset LatexCommand \index{function parameter}

\end_inset

 & Local Variables
\begin_inset LatexCommand \index{local variables}

\end_inset


\begin_inset LatexCommand \label{sec:Parameters-and-Local-Variables}

\end_inset


\end_layout

\begin_layout Standard
Automatic (local) variables and parameters to functions can either be placed
 on the stack or in data-space.
 The default action of the compiler is to place these variables in the internal
 RAM (for small model) or external RAM (for medium or large model).
 This in fact makes them similar to 
\emph on
static
\begin_inset LatexCommand \index{static}

\end_inset


\emph default
 so by default functions are non-reentrant
\begin_inset LatexCommand \index{reentrant}

\end_inset

.
 
\newline

\newline
They can be placed on the stack
\begin_inset LatexCommand \index{stack}

\end_inset

 by using the
\emph on
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset


\emph default
 option, by using 
\emph on
#pragma\InsetSpace ~
stackauto
\emph default

\begin_inset LatexCommand \index{\#pragma stackauto}

\end_inset

 or by using the 
\emph on
reentrant
\begin_inset LatexCommand \index{reentrant}

\end_inset


\emph default
 keyword in the function declaration, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
unsigned char foo(char i) __reentrant 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\end_layout

\begin_layout Standard
Since stack space on 8051 is limited, the 
\emph on
reentrant 
\emph default
keyword or the
\emph on
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\emph default
 option should be used sparingly.
 Note that the reentrant keyword just means that the parameters & local
 variables will be allocated to the stack, it 
\emph on
does not
\emph default
 mean that the function is register bank
\begin_inset LatexCommand \index{register bank (mcs51, ds390)}

\end_inset

 independent.
\newline

\newline
Local variables
\begin_inset LatexCommand \index{local variables}

\end_inset

 can be assigned storage classes and absolute
\begin_inset LatexCommand \index{Absolute addressing}

\end_inset

 addresses, e.g.: 
\end_layout

\begin_layout Verse

\family typewriter
unsigned char foo() 
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
__xdata unsigned char i;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
__bit bvar;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
__data __at
\begin_inset LatexCommand \index{at}

\end_inset

 (0x31) unsigned char j;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\end_layout

\begin_layout Standard
In the above example the variable 
\emph on
i
\emph default
 will be allocated in the external ram, 
\emph on
bvar
\emph default
 in bit addressable space and
\emph on
 j
\emph default
 in internal ram.
 When compiled with 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\emph default
 or when a function is declared as 
\emph on
reentrant
\emph default
 this should only be done for static variables.
\end_layout

\begin_layout Standard
Parameters
\begin_inset LatexCommand \index{function parameter}

\end_inset

 however are not allowed any storage class
\begin_inset LatexCommand \index{Storage class}

\end_inset

, (storage classes for parameters will be ignored), their allocation is
 governed by the memory model in use, and the reentrancy options.
\end_layout

\begin_layout Standard
It is however allowed to use bit parameters in reentrant functions and also
 non-static local bit variables are supported.
 Efficient use is limited to 8 semi-bitregisters in bit space.
 They are pushed and popped to stack
\begin_inset LatexCommand \index{stack}

\end_inset

 as a single byte just like the normal registers.
\end_layout

\begin_layout Section
Overlaying
\begin_inset LatexCommand \label{sub:Overlaying}

\end_inset


\begin_inset LatexCommand \index{Overlaying}

\end_inset


\end_layout

\begin_layout Standard
For non-reentrant
\begin_inset LatexCommand \index{reentrant}

\end_inset

 functions SDCC will try to reduce internal ram space usage by overlaying
 parameters and local variables of a function (if possible).
 Parameters and local variables
\begin_inset LatexCommand \index{local variables}

\end_inset

 of a function will be allocated to an overlayable segment if the function
 has 
\emph on
no other function calls and the function is non-reentrant and the memory
 model
\begin_inset LatexCommand \index{Memory model}

\end_inset

 is small.

\emph default
 If an explicit storage class
\begin_inset LatexCommand \index{Storage class}

\end_inset

 is specified for a local variable, it will NOT be overlayed.
\end_layout

\begin_layout Standard
Note that the compiler (not the linkage editor) makes the decision for overlayin
g the data items.
 Functions that are called from an interrupt service routine
\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
!
\end_layout

\end_inset

 should be preceded by a #pragma\InsetSpace ~
nooverlay
\begin_inset LatexCommand \index{\#pragma nooverlay}

\end_inset

 if they are not reentrant.
\end_layout

\begin_layout Standard
Also note that the compiler does not do any processing of inline assembler
 code, so the compiler might incorrectly assign local variables and parameters
 of a function into the overlay segment if the inline assembler code calls
 other c-functions that might use the overlay.
 In that case the #pragma\InsetSpace ~
nooverlay should be used.
\end_layout

\begin_layout Standard
Parameters and local variables of functions that contain 16 or 32 bit multiplica
tion
\begin_inset LatexCommand \index{Multiplication}

\end_inset

 or division
\begin_inset LatexCommand \index{Division}

\end_inset

 will NOT be overlayed since these are implemented using external functions,
 e.g.:
\end_layout

\begin_layout Verse

\family typewriter
#pragma save 
\newline
#pragma nooverlay
\begin_inset LatexCommand \index{\#pragma nooverlay}

\end_inset

 
\newline
void set_error(unsigned char errcd) 
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
P3 = errcd;
\newline
} 
\newline
#pragma restore 
\newline

\newline
void
 some_isr () __interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset

 (2)
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
set_error(10);
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\end_layout

\begin_layout Standard
In the above example the parameter 
\emph on
errcd
\emph default
 for the function 
\emph on
set_error
\emph default
 would be assigned to the overlayable segment if the #pragma\InsetSpace ~
nooverlay was
 not present, this could cause unpredictable runtime behavior when called
 from an interrupt service routine.
 The #pragma\InsetSpace ~
nooverlay ensures that the parameters and local variables for
 the function are NOT overlayed.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Interrupt Service Routines
\begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}

\end_inset


\end_layout

\begin_layout Subsection
General Information
\end_layout

\begin_layout Standard
SDCC allows 
\emph on
i
\emph default
nterrupt 
\emph on
s
\emph default
ervice 
\emph on
r
\emph default
outines to be coded in C, with some extended keywords.
\end_layout

\begin_layout Verse

\family typewriter
void timer_isr (void) __interrupt (1) __using (1) 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\end_layout

\begin_layout Standard
The optional number following the 
\emph on
interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset


\begin_inset LatexCommand \index{\_\_interrupt}

\end_inset


\emph default
 keyword is the interrupt number this routine will service.
 When present, the compiler will insert a call to this routine in the interrupt
 vector table
\begin_inset LatexCommand \index{interrupt vector table}

\end_inset

 for the interrupt number specified.
 If you have multiple source files in your project, interrupt service routines
 can be present in any of them, but a prototype of the isr MUST be present
 or included in the file that contains the function 
\emph on
main
\emph default
.
 The optional (8051 specific) keyword 
\emph on
using
\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}

\end_inset


\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}

\end_inset


\emph default
 can be used to tell the compiler to use the specified register bank when
 generating code for this function.
 
\newline
Interrupt service routines open the door for some very interesting bugs:
\end_layout

\begin_layout Subsubsection
\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-volatile}

\end_inset

Common interrupt pitfall: variable not declared 
\emph on
volatile
\end_layout

\begin_layout Standard
If an interrupt service routine changes variables which are accessed by
 other functions these variables have to be declared 
\emph on
volatile
\emph default

\begin_inset LatexCommand \index{volatile}

\end_inset

.
 See 
\begin_inset LatexCommand \url{http://en.wikipedia.org/wiki/Volatile_variable}

\end_inset

 .
\end_layout

\begin_layout Subsubsection
\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-atomic}

\end_inset

Common interrupt pitfall: 
\emph on
non-atomic access
\end_layout

\begin_layout Standard
If the access to these variables is not 
\emph on
atomic
\begin_inset LatexCommand \index{atomic}

\end_inset


\emph default
 (i.e.
 the processor needs more than one instruction for the access and could
 be interrupted while accessing the variable) the interrupt must be disabled
 during the access to avoid inconsistent data.
 
\newline
Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs
 and should be protected by disabling interrupts.
 You're not automatically on the safe side if you use 8 bit variables though.
 We need an example here: f.e.
 on the 8051 the harmless looking 
\begin_inset Quotes srd
\end_inset


\family typewriter
flags\InsetSpace ~
|=\InsetSpace ~
0x80;
\family default

\begin_inset Quotes sld
\end_inset

 is not atomic if 
\family typewriter
flags
\family default
 resides in xdata.
 Setting 
\begin_inset Quotes srd
\end_inset


\family typewriter
flags\InsetSpace ~
|=\InsetSpace ~
0x40;
\family default

\begin_inset Quotes sld
\end_inset

 from within an interrupt routine might get lost if the interrupt occurs
 at the wrong time.
 
\begin_inset Quotes sld
\end_inset


\family typewriter
counter\InsetSpace ~
+=\InsetSpace ~
8;
\family default

\begin_inset Quotes srd
\end_inset

 is not atomic on the 8051 even if 
\family typewriter
counter
\family default
 is located in data memory.
\newline
Bugs like these are hard to reproduce and can
 cause a lot of trouble.
 
\end_layout

\begin_layout Subsubsection
\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-stack-overflow}

\end_inset

Common interrupt pitfall: 
\emph on
stack overflow
\end_layout

\begin_layout Standard
The return address and the registers used in the interrupt service routine
 are saved on the stack
\begin_inset LatexCommand \index{stack}

\end_inset

 so there must be sufficient stack space.
 If there isn't variables or registers (or even the return address itself)
 will be corrupted.
 This 
\emph on
stack overflow
\emph default

\begin_inset LatexCommand \index{stack overflow}

\end_inset

 is most likely to happen if the interrupt occurs during the 
\begin_inset Quotes sld
\end_inset

deepest
\begin_inset Quotes srd
\end_inset

 subroutine when the stack is already in use for f.e.
 many return addresses.
\end_layout

\begin_layout Subsubsection
\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-reentrant}

\end_inset

Common interrupt pitfall: 
\emph on
use of non-reentrant functions
\end_layout

\begin_layout Standard
A special note here, int (16 bit) and long (32 bit) integer division
\begin_inset LatexCommand \index{Division}

\end_inset

, multiplication
\begin_inset LatexCommand \index{Multiplication}

\end_inset

 & modulus
\begin_inset LatexCommand \index{Modulus}

\end_inset

 and floating-point
\begin_inset LatexCommand \index{Floating point support}

\end_inset

 operations are implemented using external support routines.
 If an interrupt service routine needs to do any of these operations then
 the support routines (as mentioned in a following section) will have to
 be recompiled using the
\emph on
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset


\emph default
 option and the source file will need to be compiled using the 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-int-long-reent
\emph default

\begin_inset LatexCommand \index{-\/-int-long-reent}

\end_inset

 compiler option.
 
\newline
Note, the type promotion
\begin_inset LatexCommand \index{type promotion}

\end_inset

 required by ANSI C can cause 16 bit routines to be used
\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
\InsetSpace ~
!
\end_layout

\end_inset

 without the programmer being aware of it.
 See f.e.
 the cast 
\family typewriter
(unsigned char)(tail-1)
\family default
 within the if clause in section 
\begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}

\end_inset

.
\end_layout

\begin_layout Standard
Calling other functions from an interrupt service routine is not recommended,
 avoid it if possible.
 Note that when some function is called from an interrupt service routine
 it should be preceded by a #pragma\InsetSpace ~
nooverlay
\begin_inset LatexCommand \index{\#pragma nooverlay}

\end_inset

 if it is not reentrant.
 Furthermore nonreentrant functions should not be called from the main program
 while the interrupt service routine might be active.
 They also must not be called from low priority interrupt service routines
 while a high priority interrupt service routine might be active.
 You could use semaphores or make the function
\emph on
 critical
\emph default
 if all parameters are passed in registers.
\newline
 Also see section 
\begin_inset LatexCommand \ref{sub:Overlaying}

\end_inset

\InsetSpace ~
about Overlaying and section 
\begin_inset LatexCommand \ref{sub:Functions-using-private-banks}

\end_inset

\InsetSpace ~
about Functions using private register banks.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
MCS51/DS390 Interrupt Service Routines
\end_layout

\begin_layout Standard
Interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset

 numbers and the corresponding address & descriptions for the Standard 8051/8052
 are listed below.
 SDCC will automatically adjust the 
\begin_inset LatexCommand \index{interrupt vector table}

\end_inset

 to the maximum interrupt number specified.
\newline

\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="9" columns="3">
<features>
<column alignment="center" valignment="top" leftline="true" width="0in">
<column alignment="left" valignment="top" leftline="true" width="0in">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Interrupt #
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Description
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Vector Address
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
External 0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x0003
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Timer 0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x000b
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
External 1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x0013
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
3
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Timer 1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x001b
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
4
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Serial
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x0023
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
5
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Timer 2 (8052)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x002b
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
...
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
...
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
n
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x0003 + 8*n
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Standard
If the interrupt service routine is defined without 
\emph on
using
\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}

\end_inset


\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}

\end_inset


\emph default
 a register bank or with register bank 0 (
\emph on
using
\emph default
 0), the compiler will save the registers used by itself on the stack upon
 entry and restore them at exit, however if such an interrupt service routine
 calls another function then the entire register bank will be saved on the
 stack.
 This scheme may be advantageous for small interrupt service routines which
 have low register usage.
\end_layout

\begin_layout Standard
If the interrupt service routine is defined to be using a specific register
 bank then only 
\emph on
a, b, dptr
\emph default
 & psw are saved and restored, if such an interrupt service routine calls
 another function (using another register bank) then the entire register
 bank of the called function will be saved on the stack
\begin_inset LatexCommand \index{stack}

\end_inset

.
 This scheme is recommended for larger interrupt service routines.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
HC08
\begin_inset LatexCommand \index{HC08}

\end_inset

 Interrupt Service Routines
\end_layout

\begin_layout Standard
Since the number of interrupts
\begin_inset LatexCommand \index{HC08!interrupt}

\end_inset

 available is chip specific and the interrupt vector table always ends at
 the last byte of memory, the interrupt numbers corresponds to the interrupt
 vectors in reverse order of address.
 For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
 2 will use the interrupt vector at 0xfffa, and so on.
 However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
 this way; instead see section 
\begin_inset LatexCommand \ref{sub:Startup-Code}

\end_inset

 for details on customizing startup.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Z80 Interrupt Service Routines
\end_layout

\begin_layout Standard
The Z80
\begin_inset LatexCommand \index{Z80}

\end_inset

 uses several different methods for determining the correct interrupt
\begin_inset LatexCommand \index{Z80!interrupt}

\end_inset

 vector depending on the hardware implementation.
 Therefore, SDCC ignores the optional interrupt number and does not attempt
 to generate an interrupt vector table.
\end_layout

\begin_layout Standard
By default, SDCC generates code for a maskable interrupt, which uses a RETI
 instruction to return from the interrupt.
 To write an interrupt handler for the non-maskable interrupt, which needs
 a RETN instruction instead, add the 
\emph on
critical
\emph default
 keyword:
\end_layout

\begin_layout Verse

\family typewriter
void nmi_isr (void) critical interrupt
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\end_layout

\begin_layout Standard
However if you need to create a non-interruptable interrupt service routine
 you would also require the 
\emph on
critical
\emph default
 keyword.
 To distinguish between this and an nmi_isr you must provide an interrupt
 number.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Enabling and Disabling Interrupts
\end_layout

\begin_layout Subsection
Critical Functions and Critical Statements
\end_layout

\begin_layout Standard
A special keyword may be associated with a block or a function declaring
 it as 
\emph on
critical
\emph default
.
 SDCC will generate code to disable all interrupts
\begin_inset LatexCommand \index{interrupt}

\end_inset

 upon entry to a critical function and restore the interrupt enable to the
 previous state before returning.
 Nesting critical functions will need one additional byte on the stack
\begin_inset LatexCommand \index{stack}

\end_inset

 for each call.
\end_layout

\begin_layout Verse

\family typewriter
int foo () __critical
\begin_inset LatexCommand \index{critical}

\end_inset


\begin_inset LatexCommand \index{\_\_critical}

\end_inset

 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\end_layout

\begin_layout Standard
The critical attribute maybe used with other attributes like 
\emph on
reentrant.
\emph default

\newline
The keyword 
\emph on
critical
\emph default
 may also be used to disable interrupts more locally:
\end_layout

\begin_layout Verse

\family typewriter
__critical{ i++; }
\end_layout

\begin_layout Standard
More than one statement could have been included in the block.
\end_layout

\begin_layout Subsection
Enabling and Disabling Interrupts directly
\end_layout

\begin_layout Standard
Interrupts
\begin_inset LatexCommand \index{interrupt}

\end_inset

 can also be disabled and enabled directly (8051):
\end_layout

\begin_layout Verse

\family typewriter
EA = 0;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
or:\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
EA_SAVE = EA;
\end_layout

\begin_layout Verse

\family typewriter
...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
EA = 0;
\end_layout

\begin_layout Verse

\family typewriter
EA = 1;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
\end_layout

\begin_layout Verse

\family typewriter
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
EA = EA_SAVE;
\end_layout

\begin_layout Standard
On other architectures which have seperate opcodes for enabling and disabling
 interrupts you might want to make use of defines with inline assembly
\begin_inset LatexCommand \index{Assembler routines}

\end_inset

 (HC08
\begin_inset LatexCommand \index{HC08!interrupt}

\end_inset

):
\end_layout

\begin_layout Verse

\family typewriter
#define CLI _asm
\begin_inset LatexCommand \index{\_asm}

\end_inset

\InsetSpace ~
\InsetSpace ~
cli\InsetSpace ~
\InsetSpace ~
_endasm
\begin_inset LatexCommand \index{\_endasm}

\end_inset

; 
\end_layout

\begin_layout Verse

\family typewriter
#define SEI _asm\InsetSpace ~
\InsetSpace ~
sei\InsetSpace ~
\InsetSpace ~
_endasm; 
\end_layout

\begin_layout Verse

\family typewriter
...
\end_layout

\begin_layout Standard
Note: it is sometimes sufficient to disable only a specific interrupt source
 like f.e.
 a timer or serial interrupt by manipulating an 
\emph on
interrupt mask
\begin_inset LatexCommand \index{interrupt mask}

\end_inset


\emph default
 register.
 
\end_layout

\begin_layout Standard
Usually the time during which interrupts are disabled should be kept as
 short as possible.
 This minimizes both 
\emph on
interrupt latency
\emph default

\begin_inset LatexCommand \index{interrupt latency}

\end_inset

 (the time between the occurrence of the interrupt and the execution of
 the first code in the interrupt routine) and 
\emph on
interrupt jitter
\emph default

\begin_inset LatexCommand \index{interrupt jitter}

\end_inset

 (the difference between the shortest and the longest interrupt latency).
 These really are something different, f.e.
 a serial interrupt has to be served before its buffer overruns so it cares
 for the maximum interrupt latency, whereas it does not care about jitter.
 On a loudspeaker driven via a digital to analog converter which is fed
 by an interrupt a latency of a few milliseconds might be tolerable, whereas
 a much smaller jitter will be very audible.
\end_layout

\begin_layout Standard
You can reenable interrupts within an interrupt routine and on some architecture
s you can make use of two (or more) levels of 
\emph on
interrupt priorities
\emph default

\begin_inset LatexCommand \index{interrupt priority}

\end_inset

.
 On some architectures which don't support interrupt priorities these can
 be implemented by manipulating the interrupt mask and reenabling interrupts
 within the interrupt routine.
 Check there is sufficient space on the stack
\begin_inset LatexCommand \index{stack}

\end_inset

 and don't add complexity unless you have to.
 
\end_layout

\begin_layout Subsection
Semaphore
\begin_inset LatexCommand \index{semaphore}

\end_inset

 locking (mcs51/ds390)
\end_layout

\begin_layout Standard
Some architectures (mcs51/ds390) have an atomic
\begin_inset LatexCommand \index{atomic}

\end_inset

 bit test and
\emph on
 
\emph default
clear
\emph on
 
\emph default
instruction.
 These type of instructions are typically used in preemptive multitasking
 systems, where a routine f.e.
 claims the use of a data structure ('acquires a lock
\begin_inset LatexCommand \index{lock}

\end_inset

 on it'), makes some modifications and then releases the lock when the data
 structure is consistent again.
 The instruction may also be used if interrupt and non-interrupt code have
 to compete for a resource.
 With the atomic bit test and clear instruction interrupts
\begin_inset LatexCommand \index{interrupt}

\end_inset

 don't have to be disabled for the locking operation.
 
\end_layout

\begin_layout Standard
SDCC generates this instruction if the source follows this pattern:
\end_layout

\begin_layout Verse

\family typewriter
volatile
\begin_inset LatexCommand \index{volatile}

\end_inset

 bit resource_is_free; 
\newline

\newline
if (resource_is_free) 
\newline
\InsetSpace ~
\InsetSpace ~
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
resource_is_free=0; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
resource_is_free=1;
\newline
\InsetSpace ~
\InsetSpace ~
} 
\end_layout

\begin_layout Standard
Note, mcs51 and ds390 support only an atomic
\begin_inset LatexCommand \index{atomic}

\end_inset

 bit test and 
\emph on
clear
\emph default
 instruction (as opposed to atomic bit test and 
\emph on
set).
\end_layout

\begin_layout Section
Functions using private register banks
\begin_inset LatexCommand \label{sub:Functions-using-private-banks}

\end_inset

 (mcs51/ds390)
\end_layout

\begin_layout Standard
Some architectures have support for quickly changing register sets.
 SDCC supports this feature with the 
\emph on
using
\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}

\end_inset


\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}

\end_inset


\emph default
 attribute (which tells the compiler to use a register bank
\begin_inset LatexCommand \index{register bank (mcs51, ds390)}

\end_inset

 other than the default bank zero).
 It should only be applied to 
\emph on
interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset


\emph default
 functions (see footnote below).
 This will in most circumstances make the generated ISR code more efficient
 since it will not have to save registers on the stack.
\end_layout

\begin_layout Standard
The 
\emph on
using
\emph default
 attribute will have no effect on the generated code for a 
\emph on
non-interrupt
\emph default
 function (but may occasionally be useful anyway
\begin_inset Foot
status open

\begin_layout Standard
possible exception: if a function is called ONLY from 'interrupt' functions
 using a particular bank, it can be declared with the same 'using' attribute
 as the calling 'interrupt' functions.
 For instance, if you have several ISRs using bank one, and all of them
 call memcpy(), it might make sense to create a specialized version of memcpy()
 'using 1', since this would prevent the ISR from having to save bank zero
 to the stack on entry and switch to bank zero before calling the function
\end_layout

\end_inset

).
\newline

\emph on
(pending: Note, nowadays the 
\emph default
using
\emph on
 attribute has an effect on
\emph default
 
\emph on
the generated code for a 
\emph default
non-interrupt
\emph on
 function
\emph default
.
\emph on
)
\end_layout

\begin_layout Standard
An 
\emph on
interrupt
\emph default
 function using a non-zero bank will assume that it can trash that register
 bank, and will not save it.
 Since high-priority interrupts
\begin_inset LatexCommand \index{interrupts}

\end_inset


\begin_inset LatexCommand \index{interrupt priority}

\end_inset

 can interrupt low-priority ones on the 8051 and friends, this means that
 if a high-priority ISR 
\emph on
using
\emph default
 a particular bank occurs while processing a low-priority ISR 
\emph on
using
\emph default
 the same bank, terrible and bad things can happen.
 To prevent this, no single register bank should be 
\emph on
used
\emph default
 by both a high priority and a low priority ISR.
 This is probably most easily done by having all high priority ISRs use
 one bank and all low priority ISRs use another.
 If you have an ISR which can change priority at runtime, you're on your
 own: I suggest using the default bank zero and taking the small performance
 hit.
\end_layout

\begin_layout Standard
It is most efficient if your ISR calls no other functions.
 If your ISR must call other functions, it is most efficient if those functions
 use the same bank as the ISR (see note 1 below); the next best is if the
 called functions use bank zero.
 It is very inefficient to call a function using a different, non-zero bank
 from an ISR.
 
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Startup Code
\begin_inset LatexCommand \label{sub:Startup-Code}

\end_inset


\begin_inset LatexCommand \index{Startup code}

\end_inset


\end_layout

\begin_layout Subsection
MCS51/DS390 Startup Code
\end_layout

\begin_layout Standard
The compiler triggers the linker to link certain initialization modules
 from the runtime library
\begin_inset LatexCommand \index{Runtime library}

\end_inset

 called crt<something>.
 Only the necessary ones are linked, for instance crtxstack.asm (GSINIT1,
 GSINIT5) is not linked unless the -
\series bold

\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series default
-xstack option is used.
 These modules are highly entangled by the use of special segments/areas,
 but a common layout is shown below:
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(main.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area HOME (CODE)
\newline
__interrupt_vect:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ljmp __sdcc_gsinit_startup
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(crtstart.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT0 (CODE)
\newline
__sdcc_gsinit_startup::
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov sp,#__start__stack - 1
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(crtxstack.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT1 (CODE)
\newline
__sdcc_init_xstack::
\newline
; Need to initialize in GSINIT1 in
 case the user's __sdcc_external_startup uses the xstack.
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov __XPAGE,#(__start__x
stack >> 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov _spx,#__start__xstack
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(crtstart.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT2 (CODE)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
lcall __sdcc_external_startup
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov a,dpl
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
jz __sdcc_init_data
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ljmp
 __sdcc_program_startup
\newline
__sdcc_init_data:
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(crtxinit.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT3 (CODE)
\newline
__mcs51_genXINIT::
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r1,#l_XINIT
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov a,r1
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
orl a,#(l_XINIT
 >> 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
jz 00003$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r2,#((l_XINIT+255) >> 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov dptr,#s_XINIT
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r0,#s_XISEG
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov
 __XPAGE,#(s_XISEG >> 8)
\newline
00001$:\InsetSpace ~
clr a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movc a,@a+dptr
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movx @r0,a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc dptr
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc
 r0
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
cjne r0,#0,00002$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc __XPAGE
\newline
00002$:\InsetSpace ~
djnz r1,00001$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
djnz r2,00001$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov __XPAGE,#0
xFF
\newline
00003$:
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(crtclear.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT4 (CODE)
\newline
__mcs51_genRAMCLEAR::
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
clr a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r0,#(l_IRAM-1)
\newline
00004$:\InsetSpace ~
mov
 @r0,a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
djnz r0,00004$
\newline
; _mcs51_genRAMCLEAR() end
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(crtxclear.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT4 (CODE)
\newline
__mcs51_genXRAMCLEAR::
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r0,#l_PSEG
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov a,r0
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
orl a,#(l_PSEG
 >> 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
jz 00006$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r1,#s_PSEG
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov __XPAGE,#(s_PSEG >> 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
clr a
\newline
00005$:\InsetSpace ~
movx
 @r1,a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc r1
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
djnz r0,00005$
\newline
00006$:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r0,#l_XSEG
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov a,r0
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
orl a,#(l_XSEG >>
 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
jz 00008$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov r1,#((l_XSEG + 255) >> 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov dptr,#s_XSEG
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
clr a
\newline
00007$:\InsetSpace ~
movx
 @dptr,a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc dptr
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
djnz r0,00007$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
djnz r1,00007$
\newline
00008$:
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(crtxstack.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT5 (CODE)
\newline
; Need to initialize in GSINIT5 because __mcs51_genXINIT
 modifies __XPAGE
\newline
; and __mcs51_genRAMCLEAR modifies _spx.
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov __XPAGE,#(__start__x
stack >> 8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov _spx,#__start__xstack
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(application modules)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSINIT (CODE)
\end_layout

\begin_layout Verse

\family typewriter
\series bold
\size footnotesize
(main.asm)
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area GSFINAL (CODE)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ljmp __sdcc_program_startup
\newline
;---------------------------------
-----------------------
\newline
; Home
\newline
;--------------------------------------------------
------
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area HOME (CODE)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area CSEG (CODE)
\newline
__sdcc_program_startup:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
lcall _main
\newline
;
 return from main will lock up
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sjmp .
\end_layout

\begin_layout Standard
One of these modules (crtstart.asm) contains a call to the C routine 
\emph on
_sdcc_external_startup()
\begin_inset LatexCommand \index{\_sdcc\_external\_startup()}

\end_inset


\series bold
\emph default
 
\series default
at the start of the CODE area.
 This routine is also in the runtime library
\begin_inset LatexCommand \index{Runtime library}

\end_inset

 and returns 0 by default.
 If this routine returns a non-zero value, the static & global variable
 initialization will be skipped and the function main will be invoked.
 Otherwise static & global variables will be initialized before the function
 main is invoked.
 You could add an 
\emph on
_sdcc_external_startup()
\emph default
 routine to your program to override the default if you need to setup hardware
 or perform some other critical operation prior to static & global variable
 initialization
\begin_inset LatexCommand \index{Variable initialization}

\end_inset

.
 On some mcs51 variants xdata
\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}

\end_inset

 memory has to be explicitly enabled before it can be accessed or if the
 watchdog
\begin_inset LatexCommand \index{watchdog}

\end_inset

 needs to be disabled, this is the place to do it.
 The startup code clears all internal data memory, 256 bytes by default,
 but from 0 to n-1 if 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-iram-size
\begin_inset LatexCommand \index{-\/-iram-size <Value>}

\end_inset

n
\emph default
 is used.
 (recommended for Chipcon CC1010).
\end_layout

\begin_layout Standard
See also the compiler options 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-xinit
\emph default
-
\emph on
opt
\emph default

\begin_inset LatexCommand \index{-\/-no-xinit-opt}

\end_inset

, 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-main-return
\emph default

\begin_inset LatexCommand \index{-\/-main-return}

\end_inset

 and section 
\begin_inset LatexCommand \ref{sub:MCS51-variants}

\end_inset

 about MCS51-variants.
\newline

\end_layout

\begin_layout Standard
While these initialization modules are meant as generic startup code there
 might be the need for customization.
 Let's assume the return value of 
\emph on
_sdcc_external_startup()
\emph default
 in 
\emph on
crtstart.asm
\emph default
 should not be checked (or 
\emph on
_sdcc_external_startup()
\emph default
 should not be called at all).
 The recommended way would be to copy 
\emph on
crtstart.asm
\emph default
 (f.e.
 from 
\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/device/lib/mcs51/crtstart.asm}

\end_inset

) into the source directory, adapt it there, then assemble it with 
\emph on
asx8051 -plosgff
\begin_inset Foot
status open

\begin_layout Standard
\begin_inset Quotes sld
\end_inset

-plosgff
\begin_inset Quotes srd
\end_inset

 are the assembler options used in 
\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/lib/mcs51/Makefile.in?view=markup }

\end_inset


\end_layout

\end_inset

 crtstart.asm
\emph default
 and when linking your project explicitely specify 
\emph on
crtstart.rel
\emph default
.
 As a bonus a listing of the relocated object file 
\emph on
crtstart.rst
\emph default
 is generated.
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
HC08 Startup Code
\end_layout

\begin_layout Standard
The HC08
\begin_inset LatexCommand \index{HC08}

\end_inset

 startup code follows the same scheme as the MCS51 startup code.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Subsection
Z80 Startup Code
\end_layout

\begin_layout Standard
On the Z80
\begin_inset LatexCommand \index{Z80}

\end_inset

 the startup code is inserted by linking with crt0.o which is generated from
 sdcc/device/lib/z80/crt0.s.
 If you need a different startup code you can use the compiler option 
\emph on
-
\series bold
\emph default

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\series default
\emph on
-no-std-crt0
\emph default

\begin_inset LatexCommand \index{-\/-no-std-crt0}

\end_inset

 and provide your own crt0.o.
 
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Inline Assembler Code
\begin_inset LatexCommand \index{Assembler routines}

\end_inset


\end_layout

\begin_layout Subsection
A Step by Step Introduction
\begin_inset LatexCommand \label{sub:A-Step-by Assembler Introduction}

\end_inset


\end_layout

\begin_layout Standard
Starting from a small snippet of c-code this example shows for the MCS51
 how to use inline assembly, access variables, a function parameter and
 an array in xdata memory.
 The example uses an MCS51 here but is easily adapted for other architectures.
 This is a buffer routine which should be optimized:
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
unsigned char __far
\begin_inset LatexCommand \index{far (storage class)}

\end_inset


\begin_inset LatexCommand \index{\_\_far (storage class)}

\end_inset

 __at
\begin_inset LatexCommand \index{at}

\end_inset


\begin_inset LatexCommand \index{\_\_at}

\end_inset

(0x7f00) buf[0x100];
\begin_inset LatexCommand \index{Aligned array}

\end_inset


\newline
unsigned char head, tail;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* if interrupts
\begin_inset LatexCommand \index{interrupt}

\end_inset

 are involved see
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
section 
\begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}

\end_inset

 about
\series bold
 volatile
\series default
 */
\newline

\newline
void to_buffer( unsigned char c ) 
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
if( head != (unsigned char)(tail-1)
 )\InsetSpace ~
/* cast 
\series bold
needed
\series default
 to avoid promotion
\begin_inset LatexCommand \index{promotion to signed int}

\end_inset


\begin_inset LatexCommand \index{type promotion}

\end_inset

 to integer */
\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
\InsetSpace ~
!
\end_layout

\end_inset


\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
buf[ head++ ] = c;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* access to a 256 byte aligned array */
\newline
} 
\end_layout

\begin_layout Standard
If the code snippet (assume it is saved in buffer.c) is compiled with SDCC
 then a corresponding buffer.asm file is generated.
 We define a new function 
\family typewriter
to_buffer_asm()
\family default
 in file buffer.c in which we cut and paste the generated code, removing
 unwanted comments and some ':'.
 Then add 
\begin_inset Quotes sld
\end_inset


\series bold
_asm
\series default

\begin_inset Quotes srd
\end_inset

 and 
\begin_inset Quotes sld
\end_inset


\series bold
_endasm;
\series default

\begin_inset Quotes srd
\end_inset


\begin_inset Foot
status open

\begin_layout Standard
Note, that the single underscore form (_asm and _endasm) are not C99-compatible,
 and for C-99 compatibility, the double-underscore form (__asm and __endasm)
 has to be used.
 The latter is also used in the library functions.
\end_layout

\end_inset

 to the beginning and the end of the function body:
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
/* With a cut and paste from the .asm file, we have something to start with.
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
The
 function is not yet OK! (registers aren't saved) */ 
\newline
void to_buffer_asm(
 unsigned char c ) 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_asm
\begin_inset LatexCommand \index{\_asm}

\end_inset


\begin_inset LatexCommand \index{\_\_asm}

\end_inset


\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
r2,dpl 
\newline
;buffer.c if( head != (unsigned char)(tail-1) ) \InsetSpace ~
/* cast 
\series bold
needed
\series default
 to avoid promotion
\begin_inset LatexCommand \index{promotion to signed int}

\end_inset


\begin_inset LatexCommand \index{type promotion}

\end_inset

 to integer */
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
a,_tail 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dec\InsetSpace ~
\InsetSpace ~
a 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
r3,a 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
a,_head 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
cjne a,ar3,00106$ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ret
\newline
00106$:
 
\newline
;buffer.c buf[ head++ ] = c; /* access to a 256 byte aligned array */
\begin_inset LatexCommand \index{Aligned array}

\end_inset


\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
r3,_head 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc\InsetSpace ~
\InsetSpace ~
_head 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
dpl,r3 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
dph,#(_buf >> 8) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
a,r2 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movx @dptr,a
 
\newline
00103$: 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ret
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_endasm
\begin_inset LatexCommand \index{\_endasm}

\end_inset


\begin_inset LatexCommand \index{\_\_endasm}

\end_inset

;
\newline
} 
\end_layout

\begin_layout Standard
The new file buffer.c should compile with only one warning about the unreferenced
 function argument 'c'.
 Now we hand-optimize the assembly code and insert an #define USE_ASSEMBLY
 (1) and finally have:
\end_layout

\begin_layout Verse

\family typewriter
\size footnotesize
unsigned char __far __at(0x7f00) buf[0x100];
\newline
unsigned char head, tail;
\newline
#define
 USE_ASSEMBLY (1)
\newline

\newline
#if !USE_ASSEMBLY
\newline

\newline
void to_buffer( unsigned char c )
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
if(
 head != (unsigned char)(tail-1) )
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
buf[ head++ ] = c;
\newline
}
\newline

\newline
#else
\newline

\newline
void to_buffer(
 unsigned char c )
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
c; // to avoid warning: unreferenced function argument
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_asm
\begin_inset LatexCommand \index{\_asm}

\end_inset


\begin_inset LatexCommand \index{\_\_asm}

\end_inset


\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; save used registers here.
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; If we were still using r2,r3 we would have to push them here.
 
\newline
; if( head != (unsigned char)(tail-1) )
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
 a,_tail
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dec\InsetSpace ~
 a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
xrl\InsetSpace ~
 a,_head
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; we
 could do an ANL a,#0x0f here to use a smaller buffer (see below)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
jz\InsetSpace ~
\InsetSpace ~
 t_b_end$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;
\newline
;
 buf[ head++ ] = c;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
 a,dpl \InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; dpl holds lower byte of function argument
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~

 dpl,_head \InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; buf is 0x100 byte aligned so head can be used directly
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
 dph,#(_bu
f>>8)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
movx @dptr,a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc \InsetSpace ~
_head
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; we could do an ANL _head,#0x0f here to use a
 smaller buffer (see above)
\newline
t_b_end$:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; restore used registers here 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_endasm
\begin_inset LatexCommand \index{\_endasm}

\end_inset


\begin_inset LatexCommand \index{\_\_endasm}

\end_inset

;
\newline
}
\newline
#endif
\end_layout

\begin_layout Standard
The inline assembler code can contain any valid code understood by the assembler
, this includes any assembler directives and comment lines.
 The assembler does not like some characters like ':' or ''' in comments.
 You'll find an 100+ pages assembler manual in sdcc/as/doc/asxhtm.html
\begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}

\end_inset


\begin_inset LatexCommand \index{Assembler documentation}

\end_inset

 or online at 
\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}

\end_inset

\InsetSpace ~
.
\end_layout

\begin_layout Standard
The compiler does not do any validation of the code within the 
\family typewriter
_asm
\begin_inset LatexCommand \index{\_asm}

\end_inset


\begin_inset LatexCommand \index{\_\_asm}

\end_inset

 ...
 _endasm
\size footnotesize

\begin_inset LatexCommand \index{\_endasm}

\end_inset


\begin_inset LatexCommand \index{\_\_endasm}

\end_inset


\size default
;
\family default
 keyword pair.
 Specifically it will not know which registers are used and thus register
 pushing/popping
\begin_inset LatexCommand \index{push/pop}

\end_inset

 has to be done manually.
 
\end_layout

\begin_layout Standard
It is recommended that each assembly instruction (including labels) be placed
 in a separate line (as the example shows).
 When the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-
\emph on
peep-asm
\begin_inset LatexCommand \index{-\/-peep-asm}

\end_inset


\emph default
 command line option is used, the inline assembler code will be passed through
 the peephole optimizer
\begin_inset LatexCommand \index{Peephole optimizer}

\end_inset

.
 There are only a few (if any) cases where this option makes sense, it might
 cause some unexpected changes in the inline assembler code.
 Please go through the peephole optimizer rules defined in file 
\emph on
SDCCpeeph.def
\emph default
 before using this option.
\end_layout

\begin_layout Subsection
Naked Functions
\begin_inset LatexCommand \label{sub:Naked-Functions}

\end_inset


\begin_inset LatexCommand \index{Naked functions}

\end_inset


\end_layout

\begin_layout Standard
A special keyword may be associated with a function declaring it as 
\emph on
_naked
\begin_inset LatexCommand \index{\_naked}

\end_inset


\begin_inset LatexCommand \index{\_\_naked}

\end_inset

.
 
\emph default
The 
\emph on
_naked
\emph default
 function modifier attribute prevents the compiler from generating prologue
\begin_inset LatexCommand \index{function prologue}

\end_inset

 and epilogue
\begin_inset LatexCommand \index{function epilogue}

\end_inset

 code for that function.
 This means that the user is entirely responsible for such things as saving
 any registers that may need to be preserved, selecting the proper register
 bank, generating the 
\emph on
return
\emph default
 instruction at the end, etc.
 Practically, this means that the contents of the function must be written
 in inline assembler.
 This is particularly useful for interrupt functions, which can have a large
 (and often unnecessary) prologue/epilogue.
 For example, compare the code generated by these two functions:
\end_layout

\begin_layout Verse

\family typewriter
volatile
\begin_inset LatexCommand \index{volatile}

\end_inset

 data unsigned char counter;
\newline

\newline
void simpleInterrupt(void) __interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset


\begin_inset LatexCommand \index{\_\_interrupt}

\end_inset

 (1)
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
counter++;
\newline
}
\newline

\newline
void nakedInterrupt(void) __interrupt (2) __naked
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_asm
\begin_inset LatexCommand \index{\_asm}

\end_inset


\begin_inset LatexCommand \index{\_\_asm}

\end_inset


\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_counter ; does not change flags, no need to save psw
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
reti\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; MUST explicitly
 include ret or reti in _naked function.
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_endasm
\begin_inset LatexCommand \index{\_endasm}

\end_inset


\begin_inset LatexCommand \index{\_\_endasm}

\end_inset

;
\newline
}
\end_layout

\begin_layout Standard
For an 8051 target, the generated simpleInterrupt looks like:
\end_layout

\begin_layout Verse

\family typewriter
Note, this is an 
\emph on
outdated
\emph default
 example, recent versions of SDCC generate
\newline
the 
\emph on
same
\emph default
 code for simpleInterrupt() and nakedInterrupt()!
\newline

\newline
_simpleInterrupt:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
push\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
acc
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
push\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
b
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
pu
sh\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dpl
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
push\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dph
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
push\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
psw
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
psw,#0x00
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_counter
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
pop\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
psw
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
pop\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dph
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
pop\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dpl
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
pop\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
b
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
pop\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
acc
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
reti
\end_layout

\begin_layout Standard
whereas nakedInterrupt looks like:
\end_layout

\begin_layout Verse

\family typewriter
_nakedInterrupt:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
inc\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_counter ; does not change flags, no need to save psw
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
reti\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;
 MUST explicitly include ret or reti in _naked function
\end_layout

\begin_layout Standard
The related directive #pragma exclude
\begin_inset LatexCommand \index{\#pragma exclude}

\end_inset

 allows a more fine grained control over pushing & popping
\begin_inset LatexCommand \index{push/pop}

\end_inset

 the registers.
\end_layout

\begin_layout Standard
While there is nothing preventing you from writing C code inside a 
\family typewriter
_naked
\family default
 function, there are many ways to shoot yourself in the foot doing this,
 and it is recommended that you stick to inline assembler.
\end_layout

\begin_layout Subsection
Use of Labels within Inline Assembler
\end_layout

\begin_layout Standard
SDCC allows the use of in-line assembler with a few restrictions regarding
 labels.
 All labels defined within inline assembler code have to be of the form
 
\emph on
nnnnn$
\emph default
 where nnnnn is a number less than 100 (which implies a limit of utmost
 100 inline assembler labels 
\emph on
per function
\emph default
\noun on
)
\noun default
.
\begin_inset Foot
status open

\begin_layout Standard
This is a slightly more stringent rule than absolutely necessary, but stays
 always on the safe side.
 Labels in the form of nnnnn$ are local labels in the assembler, locality
 of which is confined within two labels of the standard form.
 The compiler uses the same form for labels within a function (but starting
 from nnnnn=00100); and places always a standard label at the beginning
 of a function, thus limiting the locality of labels within the scope of
 the function.
 So, if the inline assembler part would be embedded into C-code, an improperly
 placed non-local label in the assembler would break up the reference space
 for labels created by the compiler for the C-code, leading to an assembling
 error.
\end_layout

\begin_layout Standard
The numeric part of local labels does not need to have 5 digits (although
 this is the form of labels output by the compiler), any valid integer will
 do.
 Please refer to the assemblers documentation for further details.
\end_layout

\end_inset

 
\end_layout

\begin_layout Verse

\family typewriter
_asm
\begin_inset LatexCommand \index{\_asm}

\end_inset


\begin_inset LatexCommand \index{\_\_asm}

\end_inset

 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
b,#10 
\newline
00001$: 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
djnz\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
b,00001$ 
\newline
_endasm
\begin_inset LatexCommand \index{\_endasm}

\end_inset


\begin_inset LatexCommand \index{\_\_endasm}

\end_inset

 ;
\end_layout

\begin_layout Standard
Inline assembler code cannot reference any C-labels, however it can reference
 labels
\begin_inset LatexCommand \index{Labels}

\end_inset

 defined by the inline assembler, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
foo() { 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* some c code */ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_asm 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
; some assembler code 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ljmp 0003$ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_endasm;
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* some more c code */ 
\newline
clabel:\InsetSpace ~
\InsetSpace ~
/* inline assembler cannot reference this
 label */ 
\begin_inset Foot
status open

\begin_layout Standard
Here, the C-label 
\family typewriter
clabel
\family default
 is translated by the compiler into a local label, so the locality of labels
 within the function is not broken.
\end_layout

\end_inset


\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_asm
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
0003$: ;label (can be referenced by inline assembler only) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
_endasm
\begin_inset LatexCommand \index{\_endasm}

\end_inset


\begin_inset LatexCommand \index{\_\_endasm}

\end_inset

 ; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* some more c code */
\newline
}
\end_layout

\begin_layout Standard
In other words inline assembly code can access labels defined in inline
 assembly within the scope of the function.
 The same goes the other way, i.e.
 labels defines in inline assembly can not be accessed by C statements.
\end_layout

\begin_layout Section
Interfacing with Assembler Code
\begin_inset LatexCommand \index{Assembler routines}

\end_inset


\end_layout

\begin_layout Subsection
Global Registers used for Parameter Passing
\begin_inset LatexCommand \index{Parameter passing}

\end_inset


\end_layout

\begin_layout Standard
The compiler always uses the global registers 
\emph on
DPL, DPH
\begin_inset LatexCommand \index{DPTR, DPH, DPL}

\end_inset


\begin_inset LatexCommand \index{DPTR}

\end_inset

, B
\begin_inset LatexCommand \index{B (mcs51, ds390 register)}

\end_inset

 
\emph default
and
\emph on
 ACC
\begin_inset LatexCommand \index{ACC (mcs51, ds390 register)}

\end_inset


\emph default
 to pass the first (non-bit) parameter to a function, and also to pass the
 return value 
\begin_inset LatexCommand \index{return value}

\end_inset

of function; according to the following scheme: one byte return value in
 
\emph on
DPL
\emph default
, two byte value in 
\emph on
DPL
\emph default
 (LSB) and 
\emph on
DPH
\emph default
 (MSB).
 three byte values (generic pointers) in 
\emph on
DPH
\emph default
, 
\emph on
DPL
\emph default
 and 
\emph on
B
\emph default
, and four byte values in 
\emph on
DPH
\emph default
, 
\emph on
DPL
\emph default
,
\emph on
 B
\emph default
 and 
\emph on
ACC
\emph default
.
 Generic pointers
\begin_inset LatexCommand \index{generic pointer}

\end_inset

 contain type of accessed memory in 
\emph on
B
\emph default
: 
\series bold
0x00
\series default
 -- xdata/far, 
\series bold
0x40
\series default
 -- idata/near -- , 
\series bold
0x60
\series default
 -- pdata, 
\series bold
0x80
\series default
 -- code
\begin_inset Note Note
status collapsed

\begin_layout Standard
This might not be the case of certain memory models (medium???)
\end_layout

\end_inset

.
\end_layout

\begin_layout Standard
The second parameter onwards is either allocated on the stack (for reentrant
 routines or if -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto is used) or in data/xdata memory (depending on the memory model).
\end_layout

\begin_layout Standard
Bit parameters are passed in a virtual register called 'bits' in bit-addressable
 space for reentrant functions or allocated directly in bit memory otherwise.
\end_layout

\begin_layout Standard
Functions (with two or more parameters or bit parameters) that are called
 through function pointers
\begin_inset LatexCommand \index{function pointers}

\end_inset

 must therefor be reentrant so the compiler knows how to pass the parameters.
\end_layout

\begin_layout Subsection
Registers usage
\end_layout

\begin_layout Standard
Unless the called function is declared as 
\family typewriter
_naked
\family default

\begin_inset LatexCommand \index{naked}

\end_inset

, or the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves
\begin_inset LatexCommand \index{-\/-callee-saves}

\end_inset

/-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-all-callee-saves command line option or the corresponding callee_saves
 pragma are used, the caller will save the registers (
\emph on
R0-R7
\emph default
) around the call, so the called function can destroy they content freely.
\end_layout

\begin_layout Standard
If the called function is not declared as 
\family typewriter
_naked
\family default
, the caller will swap register banks around the call, if caller and callee
 use different register banks (having them defined by the 
\family typewriter
_using
\family default
 modifier).
 
\end_layout

\begin_layout Standard
The called function can also use 
\emph on
DPL
\emph default
, 
\emph on
DPH
\emph default
, 
\emph on
B
\emph default
 and 
\emph on
ACC
\emph default
 observing that they are used for parameter/return value passing.
\end_layout

\begin_layout Subsection
Assembler Routine (non-reentrant)
\end_layout

\begin_layout Standard
In the following example
\begin_inset LatexCommand \index{reentrant}

\end_inset


\begin_inset LatexCommand \index{Assembler routines (non-reentrant)}

\end_inset

 the function c_func calls an assembler routine asm_func, which takes two
 parameters
\begin_inset LatexCommand \index{function parameter}

\end_inset

.
\end_layout

\begin_layout Verse

\family typewriter
extern int asm_func(unsigned char, unsigned char);
\newline

\newline
int c_func (unsigned char
 i, unsigned char j)
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
return asm_func(i,j);
\newline
}
\newline

\newline
int main()
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
return c_func(10,9);
\newline
}
\end_layout

\begin_layout Standard
The corresponding assembler function is:
\end_layout

\begin_layout Verse

\family typewriter
.globl _asm_func_PARM_2 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.globl _asm_func 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area OSEG 
\newline
_asm_func_PARM_2:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.ds   
 1 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
.area CSEG 
\newline
_asm_func: 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
a,dpl 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
add\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
a,_asm_func_PARM_2 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dpl,a 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
dph
\begin_inset LatexCommand \index{DPTR, DPH, DPL}

\end_inset

,#0x00 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ret
\end_layout

\begin_layout Standard
The parameter naming convention is _<function_name>_PARM_<n>, where n is
 the parameter number starting from 1, and counting from the left.
 The first parameter is passed in 
\emph on
DPH
\emph default
, 
\emph on
DPL
\emph default
, 
\emph on
B
\emph default
 and 
\emph on
ACC
\emph default
 according to the description above.
 The variable name for the second parameter will be _<function_name>_PARM_2.
\newline

\newline
Assem
ble the assembler routine with the following command:
\newline

\newline

\family sans
\series bold
asx8051 -losg asmfunc.asm
\newline

\newline

\family default
\series default
Then compile and link the assembler routine to the C source file with the
 following command:
\newline

\newline

\family sans
\series bold
sdcc cfunc.c asmfunc.rel
\end_layout

\begin_layout Subsection
Assembler Routine (reentrant)
\end_layout

\begin_layout Standard
In this case
\begin_inset LatexCommand \index{reentrant}

\end_inset


\begin_inset LatexCommand \index{Assembler routines (reentrant)}

\end_inset

 the second parameter
\begin_inset LatexCommand \index{function parameter}

\end_inset

 onwards will be passed on the stack, the parameters are pushed from right
 to left i.e.
 before the call the second leftmost parameter will be on the top of the
 stack (the leftmost parameter is passed in registers).
 Here is an example:
\end_layout

\begin_layout Verse

\family typewriter
extern int asm_func(unsigned char, unsigned char, unsigned char) reentrant;
\newline

\newline
int
 c_func (unsigned char i, unsigned char j, unsigned char k) reentrant 
\newline
{
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
return asm_func(i,j,k); 
\newline
} 
\newline

\newline
int main() 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
return c_func(10,9,8); 
\newline
}
\end_layout

\begin_layout Standard
The corresponding (unoptimized) assembler routine is:
\end_layout

\begin_layout Verse

\family typewriter
.globl _asm_func 
\newline
_asm_func: 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
push\InsetSpace ~
_bp 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
_bp,sp\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;stack contains: _bp, return
 address, second parameter, third parameter
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
r2,dpl
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
a,_bp
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
add\InsetSpace ~
\InsetSpace ~
a,#0xfd\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;calculate
 pointer to the second parameter
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
r0,a 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
a,_bp 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
add\InsetSpace ~
\InsetSpace ~
a,#0xfc\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;calculate pointer
 to the rightmost parameter
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
r1,a 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
a,@r0
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
add\InsetSpace ~
\InsetSpace ~
a,@r1
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
add\InsetSpace ~
\InsetSpace ~
a,r2\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;calculate the
 result (= sum of all three parameters)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
dpl,a\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;return value goes into dptr
 (cast into int)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
dph,#0x00 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov\InsetSpace ~
\InsetSpace ~
sp,_bp 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
pop\InsetSpace ~
\InsetSpace ~
_bp 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ret
\end_layout

\begin_layout Standard
The compiling and linking procedure remains the same, however note the extra
 entry & exit linkage required for the assembler code, _bp is the stack
 frame pointer and is used to compute the offset into the stack for parameters
 and local variables.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
int (16 bit)
\begin_inset LatexCommand \index{int (16 bit)}

\end_inset

 and long (32 bit)
\begin_inset LatexCommand \index{long (32 bit)}

\end_inset

 Support
\end_layout

\begin_layout Standard
For signed & unsigned int (16 bit) and long (32 bit) variables, division,
 multiplication and modulus operations are implemented by support routines.
 These support routines are all developed in ANSI-C to facilitate porting
 to other MCUs, although some model specific assembler optimizations are
 used.
 The following files contain the described routines, all of them can be
 found in <installdir>/share/sdcc/lib.
\newline

\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="11" columns="2">
<features>
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Function
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Description
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_mulint.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
16 bit multiplication
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_divsint.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
 signed 16 bit division (calls _divuint)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_divuint.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
 unsigned 16 bit division
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_modsint.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
signed 16 bit modulus (calls _moduint)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_moduint.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
unsigned 16 bit modulus
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_mullong.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
32 bit multiplication
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_divslong.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
 signed 32 division (calls _divulong)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_divulong.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
unsigned 32 division
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_modslong.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
 signed 32 bit modulus (calls _modulong)
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_modulong.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
unsigned 32 bit modulus
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Standard
Since they are compiled as 
\emph on
non-reentrant
\emph default

\begin_inset LatexCommand \index{reentrant}

\end_inset

, interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset

 service routines should not do any of the above operations.
 If this is unavoidable then the above routines will need to be compiled
 with the 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset


\emph default
 option, after which the source program will have to be compiled with 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-int-long-reent
\begin_inset LatexCommand \index{-\/-int-long-reent}

\end_inset


\emph default
 option.
 Notice that you don't have to call these routines directly.
 The compiler will use them automatically every time an integer operation
 is required.
\end_layout

\begin_layout Section
Floating Point Support
\begin_inset LatexCommand \index{Floating point support}

\end_inset


\end_layout

\begin_layout Standard
SDCC supports IEEE (single precision 4 bytes) floating point numbers.
 The floating point support routines are derived from gcc's floatlib.c and
 consist of the following routines:
\newline

\end_layout

\begin_layout Standard
\align center

\size footnotesize
\begin_inset Tabular
<lyxtabular version="3" rows="17" columns="2">
<features>
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
Function 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Description
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fsadd.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
add floating point numbers
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fssub.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
subtract floating point numbers 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fsdiv.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
divide floating point numbers 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fsmul.c 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
multiply floating point numbers 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fs2uchar.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
convert floating point to unsigned char
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fs2char.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
convert floating point to signed char
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fs2uint.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
convert floating point to unsigned int
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fs2int.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
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convert floating point to signed int
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
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\emph off
\bar no
\noun off
\color none
_fs2ulong.
\family default
\series default
\shape default
\size default
\emph default
\bar default
\noun default
c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
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convert floating point to unsigned long
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_fs2long.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
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\emph off
\bar no
\noun off
\color none
convert floating point to signed long
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_uchar2fs.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
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\color none
convert unsigned char to floating point
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_char2fs.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
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\color none
convert char to floating point number
\end_layout

\end_inset
</cell>
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<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
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\color none
_uint2fs.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
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\bar no
\noun off
\color none
convert unsigned int to floating point
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_int2fs.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
convert int to floating point numbers
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_ulong2fs.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
convert unsigned long to floating point number
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
_long2fs.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
convert long to floating point number
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Standard
These support routines are developed in ANSI-C so there is room for space
 and speed improvement
\begin_inset Foot
status open

\begin_layout Standard
These floating point routines (
\emph on
not
\emph default
 sinf(), cosf(), ...) for the mcs51 are implemented in assembler.
 
\end_layout

\end_inset

.
 Note if all these routines are used simultaneously the data space might
 overflow.
 For serious floating point usage the large model might be needed.
 Also notice that you don't have to call this routines directly.
 The compiler will use them automatically every time a floating point operation
 is required.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Library Routines
\begin_inset LatexCommand \index{Libraries}

\end_inset


\end_layout

\begin_layout Standard

\emph on
<pending: this is messy and incomplete - a little more information is in
 sdcc/doc/libdoc.txt
\emph default
 >
\end_layout

\begin_layout Subsection
Compiler support routines (_gptrget, _mulint etc.)
\end_layout

\begin_layout Subsection
Stdclib functions (puts, printf, strcat etc.)
\end_layout

\begin_layout Subsubsection
<stdio.h>
\end_layout

\begin_layout Paragraph
getchar(), putchar()
\end_layout

\begin_layout Standard
\begin_inset LatexCommand \index{<stdio.h>}

\end_inset

As usual on embedded systems you have to provide your own 
\family typewriter
getchar()
\begin_inset LatexCommand \index{getchar()}

\end_inset

 
\family default
and 
\family typewriter
putchar()
\begin_inset LatexCommand \index{putchar()}

\end_inset


\family default
 routines.
 SDCC does not know whether the system connects to a serial line with or
 without handshake, LCD, keyboard or other device.
 And whether a 
\family typewriter
lf
\family default
 to 
\family typewriter
crlf
\family default
 conversion within 
\family typewriter
putchar()
\family default
 is intended.
 You'll find examples for serial routines f.e.
 in sdcc/device/lib.
 For the mcs51 this minimalistic polling 
\family typewriter
putchar()
\family default
 routine might be a start:
\end_layout

\begin_layout Verse

\family typewriter
void putchar (char c) { 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
while (!TI)\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 /* assumes UART is initialized */
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
TI
 = 0;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SBUF = c;
\newline
}
\end_layout

\begin_layout Paragraph
printf()
\end_layout

\begin_layout Standard
The default
\family typewriter
 printf()
\begin_inset LatexCommand \index{printf()}

\end_inset


\family default
 implementation in
\family typewriter
 printf_large.c
\family default
 does not support float (except on ds390).
 To enable this recompile it with the option 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

DUSE_FLOATS=1
\begin_inset LatexCommand \index{USE\_FLOATS}

\end_inset


\emph default
 on the command line.
 Use
\emph on
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-large
\begin_inset LatexCommand \index{-\/-model-large}

\end_inset


\emph default
 for the mcs51 port, since this uses a lot of memory.
\end_layout

\begin_layout Standard
If you're short on code memory you might want to use 
\family typewriter
printf_small()
\begin_inset LatexCommand \index{printf\_small()}

\end_inset


\family default
 
\emph on
instead
\emph default
 of
\family typewriter
 printf().

\family default
 For the mcs51 there additionally are assembly versions 
\family typewriter
printf_tiny()
\begin_inset LatexCommand \index{printf\_tiny() (mcs51)}

\end_inset


\family default
 (subset of printf using less than 270 bytes) and 
\family typewriter
printf_fast()
\begin_inset LatexCommand \index{printf\_fast() (mcs51)}

\end_inset

 
\family default
and
\family typewriter
 printf_fast_f()
\begin_inset LatexCommand \index{printf\_fast\_f() (mcs51)}

\end_inset


\family default
 (floating-point aware version of printf_fast) which should fit the requirements
 of many embedded systems (printf_fast() can be customized by unsetting
 #defines to 
\emph on
not
\emph default
 support long variables and field widths).
 Be sure to use only one of these printf options within a project.
\newline

\end_layout

\begin_layout Standard
Feature matrix of different 
\emph on
printf
\emph default
 options on mcs51.
\end_layout

\begin_layout Standard
\begin_inset Tabular
<lyxtabular version="3" rows="14" columns="7">
<features islongtable="true">
<column alignment="left" valignment="middle" leftline="true" width="14col%">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="12col%">
<column alignment="center" valignment="top" leftline="true" width="10col%">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="12col%">
<column alignment="center" valignment="top" rightline="true" width="0">
<row topline="true" bottomline="true" endhead="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
\size large
mcs51
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
printf
\begin_inset LatexCommand \index{printf}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
printf 
\size scriptsize
USE_FLOATS=1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
printf_small
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
printf_fast
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
printf_fast_f
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
printf_tiny
\end_layout

\end_inset
</cell>
</row>
<row topline="true" endhead="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
filename
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size scriptsize
printf_large.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size scriptsize
printf_large.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size scriptsize
printfl.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size scriptsize
printf_fast.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size scriptsize
printf_fast_f.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size scriptsize
printf_tiny.c
\end_layout

\end_inset
</cell>
</row>
<row topline="true" endhead="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset Quotes sld
\end_inset

Hello World
\begin_inset Quotes srd
\end_inset

 size
\end_layout

\begin_layout Standard
small / large
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.7k / 2.4k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
4.3k / 5.6k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.2k / 1.8k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.3k / 1.3k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.9k / 1.9k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.44k / 0.44k
\end_layout

\end_inset
</cell>
</row>
<row topline="true" endhead="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
code size
\end_layout

\begin_layout Standard
small / large
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.4k / 2.0k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
2.8k / 3.7k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.45k / 0.47k (+ _ltoa)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.2k / 1.2k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.6k / 1.6k
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.26k / 0.26k
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
formats
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
cdi
\emph on
o
\emph default
psux
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
cd
\family default
\series default
\shape default
\size default
\emph default
\bar default
\noun default
f
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
i
\family default
\series default
\shape default
\size default
\emph on
\bar default
\noun default
o
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
psux
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
c
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
d
\family default
\series default
\shape default
\size default
\emph on
\bar default
\noun default
o
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
s
\family default
\series default
\shape default
\size default
\emph default
\bar default
\noun default
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
cdsux
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
cdfsux
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
cdsux
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
long (32 bit) support
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
byte arguments on stack
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
b
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
b
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
float format
\begin_inset LatexCommand \index{Floating point support}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
%f
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
%f
\begin_inset Foot
status collapsed

\begin_layout Standard
Range limited to +/- 4294967040, precision limited to 8 digits past decimal
\end_layout

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
float formats %e %g
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
field width
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
x
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
string speed
\begin_inset Foot
status collapsed

\begin_layout Standard
Execution time of printf("%s%c%s%c%c%c", "Hello", ' ', "World", '!', '
\backslash
r', '
\backslash
n'); standard 8051 @ 22.1184 MHz, empty putchar()
\end_layout

\end_inset

,
\end_layout

\begin_layout Standard
small / large
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.52 / 2.59 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.53 / 2.62 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.92 / 0.93 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.45 / 0.45 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.46 / 0.46 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.45 / 0.45 ms
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
int speed
\begin_inset Foot
status collapsed

\begin_layout Standard
Execution time of printf("%d", -12345); standard 8051 @ 22.1184 MHz, empty
 putchar()
\end_layout

\end_inset

,
\end_layout

\begin_layout Standard
small / large
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
3.01 / 3.61 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
3.01 / 3.61 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
3.51 / 18.13 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.22 / 0.22 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.23 / 0.23 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.25 / 0.25 ms
\begin_inset Foot
status collapsed

\begin_layout Standard
printf_tiny integer speed is data dependent, worst case is 0.33 ms
\end_layout

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
long speed
\begin_inset Foot
status collapsed

\begin_layout Standard
Execution time of printf("%ld", -123456789); standard 8051 @ 22.1184 MHz,
 empty putchar()
\end_layout

\end_inset

,
\end_layout

\begin_layout Standard
small / large
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
5.37 / 6.31 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
5.37 / 6.31 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
8.71 / 40.65 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.40 / 0.40 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0.40 / 0.40 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
float speed
\begin_inset Foot
status collapsed

\begin_layout Standard
Execution time of printf("%.3f", -12345.678); standard 8051 @ 22.1184 MHz,
 empty putchar()
\end_layout

\end_inset

,
\end_layout

\begin_layout Standard
small / large
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
7.49 / 22.47 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1.04 / 1.04 ms
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Subsubsection
<malloc.h>
\begin_inset LatexCommand \index{malloc.h}

\end_inset


\end_layout

\begin_layout Standard
As of SDCC 2.6.2 you no longer need to call an initialization routine before
 using dynamic memory allocation
\begin_inset LatexCommand \index{dynamic memory allocation (malloc)}

\end_inset

 and a default heap
\begin_inset LatexCommand \index{heap (malloc)}

\end_inset

 space of 1024 bytes is provided for malloc to allocate memory from.
 If you need a different heap size you need to recompile _heap.c with the
 required size defined in HEAP_SIZE.
 It is recommended to make a copy of this file into your project directory
 and compile it there with:
\end_layout

\begin_layout Verse

\family typewriter
sdcc -c _heap.c -D HEAD_SIZE=2048
\end_layout

\begin_layout Standard
And then link it with:
\end_layout

\begin_layout Verse

\family typewriter
sdcc main.rel _heap.rel
\end_layout

\begin_layout Subsection
Math functions (sinf, powf, sqrtf etc.)
\end_layout

\begin_layout Subsubsection
<math.h>
\end_layout

\begin_layout Standard
See definitions in file <math.h>.
\end_layout

\begin_layout Subsection
Other libraries
\end_layout

\begin_layout Standard
Libraries
\begin_inset LatexCommand \index{Libraries}

\end_inset

 included in SDCC should have a license at least as liberal as the GNU Lesser
 General Public License
\begin_inset LatexCommand \index{GNU Lesser General Public License, LGPL}

\end_inset

 
\emph on
LGPL
\emph default
.
\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
license statements for the libraries are missing.
 sdcc/device/lib/ser_ir.c
\end_layout

\begin_layout Standard
or _decdptr f.e.
 come with a GPL (as opposed to LGPL) License - this will not be liberal
 enough for many embedded programmers.
\end_layout

\end_inset


\end_layout

\begin_layout Standard
If you have ported some library or want to share experience about some code
 which f.e.
 falls into any of these categories Busses (I
\begin_inset Formula $^{\textrm{2}}$
\end_inset

C, CAN, Ethernet, Profibus, Modbus, USB, SPI, JTAG ...), Media (IDE, Memory
 cards, eeprom, flash...), En-/Decryption, Remote debugging, Realtime kernel,
 Keyboard, LCD, RTC, FPGA, PID then the sdcc-user mailing list 
\begin_inset LatexCommand \url{http://sourceforge.net/mail/?group_id=599}

\end_inset

\InsetSpace ~
would certainly like to hear about it.
\end_layout

\begin_layout Standard
Programmers coding for embedded systems are not especially famous for being
 enthusiastic, so don't expect a big hurray but as the mailing list is searchabl
e these references are very valuable.
 Let's help to create a climate where information is shared.
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
Memory Models
\end_layout

\begin_layout Subsection
MCS51 Memory Models
\begin_inset LatexCommand \index{Memory model}

\end_inset


\begin_inset LatexCommand \index{MCS51 memory model}

\end_inset


\end_layout

\begin_layout Subsubsection
Small, Medium and Large
\end_layout

\begin_layout Standard
SDCC allows three memory models for MCS51 code, 
\shape slanted
small, medium
\shape default
 and 
\shape slanted
large
\shape default
.
 Modules compiled with different memory models should 
\emph on
never
\emph default
 be combined together or the results would be unpredictable.
 The library routines supplied with the compiler are compiled as small,
 medium and large.
 The compiled library modules are contained in separate directories as small,
 medium and large so that you can link to the appropriate set.
\end_layout

\begin_layout Standard
When the medium or large model is used all variables declared without a
 storage class will be allocated into the external ram, this includes all
 parameters and local variables (for non-reentrant
\begin_inset LatexCommand \index{reentrant}

\end_inset

 functions).
 When the small model is used variables without storage class are allocated
 in the internal ram.
\end_layout

\begin_layout Standard
Judicious usage of the processor specific storage classes
\begin_inset LatexCommand \index{Storage class}

\end_inset

 and the 'reentrant' function type will yield much more efficient code,
 than using the large model.
 Several optimizations are disabled when the program is compiled using the
 large model, it is therefore recommended that the small model be used unless
 absolutely required.
\end_layout

\begin_layout Subsubsection
External Stack
\begin_inset LatexCommand \label{sub:External-Stack}

\end_inset


\begin_inset LatexCommand \index{stack}

\end_inset


\begin_inset LatexCommand \index{External stack (mcs51)}

\end_inset


\end_layout

\begin_layout Standard
The external stack (-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack option
\begin_inset LatexCommand \index{-\/-xstack}

\end_inset

) is located in pdata
\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}

\end_inset

 memory (usually at the start of the external ram segment) and uses all
 unused space in pdata (max.
 256 bytes).
 When -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack option is used to compile the program, the parameters and local
 variables
\begin_inset LatexCommand \index{local variables}

\end_inset

 of all reentrant functions are allocated in this area.
 This option is provided for programs with large stack space requirements.
 When used with the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset

 option, all parameters and local variables are allocated on the external
 stack (note: support libraries will need to be recompiled with the same
 options.
 There is a predefined target in the library makefile).
\end_layout

\begin_layout Standard
The compiler outputs the higher order address byte of the external ram segment
 into port P2
\begin_inset LatexCommand \index{P2 (mcs51 sfr)}

\end_inset

 (see also section 
\begin_inset LatexCommand \ref{sub:MCS51-variants}

\end_inset

), therefore when using the External Stack option, this port 
\emph on
may not
\emph default
 be used by the application program.
\end_layout

\begin_layout Subsection
DS390 Memory Model
\begin_inset LatexCommand \index{Memory model}

\end_inset


\begin_inset LatexCommand \index{DS390 memory model}

\end_inset


\end_layout

\begin_layout Standard
The only model supported is Flat 24
\begin_inset LatexCommand \index{Flat 24 (DS390 memory model)}

\end_inset

.
 This generates code for the 24 bit contiguous addressing mode of the Dallas
 DS80C390 part.
 In this mode, up to four meg of external RAM or code space can be directly
 addressed.
 See the data sheets at www.dalsemi.com for further information on this part.
\newline

\newline
Note
 that the compiler does not generate any code to place the processor into
 24 bitmode (although 
\emph on
tinibios
\emph default
 in the ds390 libraries will do that for you).
 If you don't use 
\emph on
tinibios
\emph default

\begin_inset LatexCommand \index{Tinibios (DS390)}

\end_inset

, the boot loader or similar code must ensure that the processor is in 24
 bit contiguous addressing mode before calling the SDCC startup code.
\newline

\newline
Like
 the 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-large
\emph default
 option, variables will by default be placed into the XDATA segment.
 
\newline

\newline
Segments may be placed anywhere in the 4 meg address space using the usual
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-*-loc options.
 Note that if any segments are located above 64K, the -r flag must be passed
 to the linker to generate the proper segment relocations, and the Intel
 HEX output format must be used.
 The -r flag can be passed to the linker by using the option 
\emph on
-Wl-r
\emph default
 on the SDCC command line.
 However, currently the linker can not handle code segments > 64k.
\end_layout

\begin_layout Section
Pragmas
\begin_inset LatexCommand \label{sec:Pragmas}

\end_inset


\begin_inset LatexCommand \index{Pragmas}

\end_inset


\end_layout

\begin_layout Standard
Pragmas are used to turn on and/or off certain compiler options.
 Some of them are closely related to corresponding command-line options
 (see section 
\begin_inset LatexCommand \vref{sec:Command-Line-Options}

\end_inset

).
\newline
Pragmas should be placed before and/or after a function, placing pragmas
 inside a function body could have unpredictable results.
\newline

\newline
SDCC supports the
 following #pragma directives:
\end_layout

\begin_layout Itemize

\series bold
save
\series default

\begin_inset LatexCommand \index{\#pragma save}

\end_inset

 - this will save most current options to the save/restore stack.
 See #pragma\InsetSpace ~
restore.
\end_layout

\begin_layout Itemize

\series bold
restore
\series default

\begin_inset LatexCommand \index{\#pragma restore}

\end_inset

 - will restore saved options from the last save.
 saves & restores can be nested.
 SDCC uses a save/restore stack: save pushes current options to the stack,
 restore pulls current options from the stack.
 See #pragma\InsetSpace ~
save.
\newline

\end_layout

\begin_layout Itemize

\series bold
callee_saves
\series default

\begin_inset LatexCommand \index{\#pragma callee\_saves}

\end_inset


\begin_inset LatexCommand \index{function prologue}

\end_inset

 function1[,function2[,function3...]] 
\begin_inset LatexCommand \label{ite:callee_saves-function1[,function2[,function3...]]--}

\end_inset

- The compiler by default uses a caller saves convention for register saving
 across function calls, however this can cause unnecessary register pushing
 and popping
\begin_inset LatexCommand \index{push/pop}

\end_inset

 when calling small functions from larger functions.
 This option can be used to switch off the register saving convention for
 the function names specified.
 The compiler will not save registers when calling these functions, extra
 code need to be manually inserted at the entry and exit for these functions
 to save and restore the registers used by these functions, this can SUBSTANTIAL
LY reduce code and improve run time performance of the generated code.
 In the future the compiler (with inter procedural analysis) may be able
 to determine the appropriate scheme to use for each function call.
 If -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves command line option is used (see page 
\begin_inset LatexCommand \vpageref{lyx:--callee-saves-function1[,function2][,function3]...}

\end_inset

), the function names specified in #pragma\InsetSpace ~
callee_saves
\begin_inset LatexCommand \index{\#pragma callee\_saves}

\end_inset

 is appended to the list of functions specified in the command line.
\end_layout

\begin_layout Itemize

\series bold
exclude
\series default

\begin_inset LatexCommand \index{\#pragma exclude}

\end_inset

 none | {acc[,b[,dpl[,dph]]] - The exclude pragma disables the generation
 of pairs of push/pop
\begin_inset LatexCommand \index{push/pop}

\end_inset

 instructions in 
\emph on
I
\emph default
nterrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset

 
\emph on
S
\emph default
ervice 
\emph on
R
\emph default
outines.
 The directive should be placed immediately before the ISR function definition
 and it affects ALL ISR functions following it.
 To enable the normal register saving for ISR functions use #pragma\InsetSpace ~
exclude\InsetSpace ~
none
\begin_inset LatexCommand \index{\#pragma exclude}

\end_inset

.
 See also the related keyword _naked
\begin_inset LatexCommand \index{\_naked}

\end_inset


\begin_inset LatexCommand \index{\_\_naked}

\end_inset

.
\end_layout

\begin_layout Itemize

\series bold
less_pedantic
\series default

\begin_inset LatexCommand \index{pedantic}

\end_inset


\begin_inset LatexCommand \index{\#pragma less\_pedantic}

\end_inset

 
\begin_inset LatexCommand \label{ite:less_pedantic}

\end_inset

- the compiler will not warn you anymore for obvious mistakes, you're on
 your own now ;-( .
 See also the command line option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-less-pedantic 
\begin_inset LatexCommand \vpageref{lyx:--less-pedantic}

\end_inset

.
 
\newline
More specifically, the following warnings will be disabled: 
\shape italic
comparison is always [true/false] due to limited range of data type
\shape default
 (94); 
\shape italic
overflow in implicit constant conversion
\shape default
 (158); [the (in)famous] 
\shape italic
conditional flow changed by optimizer: so said EVELYN the modified DOG
\shape default
 (110); 
\shape italic
function '[function name]' must return value
\shape default
 (59).
 
\newline
Furthermore, warnings of less importance (of PEDANTIC and INFO warning
 level) are disabled, too, namely: 
\shape italic
constant value '[
\begin_inset Note Note
status collapsed

\begin_layout Standard
dunno what comes here - this warning appears to be unused altogether
\end_layout

\end_inset

]', out of range
\shape default
 (81); 
\shape italic
[left/right] shifting more than size of object changed to zero
\shape default
 (116); 
\shape italic
unreachable code
\shape default
 (126); 
\shape italic
integer overflow in expression
\shape default
 (165); 
\shape italic
unmatched #pragma save and #pragma restore
\shape default
 (170); 
\shape italic
comparison of 'signed char' with 'unsigned char' requires promotion to int
\shape default
 (185); 
\shape italic
ISO C90 does not support flexible array members
\shape default
 (187); 
\shape italic
extended stack by [number] bytes for compiler temp(s) :in function '[function\InsetSpace ~
nam
e]':\InsetSpace ~
[
\begin_inset Note Note
status collapsed

\begin_layout Standard
appears to be always blank - what was supposed to be here?
\end_layout

\end_inset

]
\shape default
 (114); 
\shape italic
function '[function name]', # edges [number] , # nodes [number] , cyclomatic
 complexity [number]
\shape default
 (121).
\end_layout

\begin_layout Itemize

\series bold
disable_warning
\series default
 <nnnn>
\begin_inset LatexCommand \index{\#pragma disable\_warning}

\end_inset

 - the compiler will not warn you anymore about warning number <nnnn>.
\end_layout

\begin_layout Itemize

\series bold
nogcse
\series default

\begin_inset LatexCommand \index{\#pragma nogcse}

\end_inset

 - will stop global common subexpression elimination.
\end_layout

\begin_layout Itemize

\series bold
noinduction
\series default

\begin_inset LatexCommand \index{\#pragma noinduction}

\end_inset

 - will stop loop induction optimizations.
\end_layout

\begin_layout Itemize

\series bold
noinvariant
\series default

\begin_inset LatexCommand \index{\#pragma noinvariant}

\end_inset

 - will not do loop invariant optimizations.
 For more details see Loop Invariants in section
\begin_inset LatexCommand \ref{sub:Loop-Optimizations}

\end_inset

.
\end_layout

\begin_layout Itemize

\series bold
noiv
\series default

\begin_inset LatexCommand \index{\#pragma noiv}

\end_inset

 - Do not generate interrupt
\begin_inset LatexCommand \index{interrupt}

\end_inset

 vector table
\begin_inset LatexCommand \index{interrupt vector table}

\end_inset

 entries for all ISR functions defined after the pragma.
 This is useful in cases where the interrupt vector table must be defined
 manually, or when there is a secondary, manually defined interrupt vector
 table (e.g.
 for the autovector feature of the Cypress EZ-USB FX2).
 More elegantly this can be achieved by obmitting the optional interrupt
 number after the interrupt keyword, see section 
\begin_inset LatexCommand \ref{sub:Interrupt-Service-Routines}

\end_inset

\InsetSpace ~
about interrupts.
\end_layout

\begin_layout Itemize

\series bold
nojtbound
\series default

\begin_inset LatexCommand \index{\#pragma nojtbound}

\end_inset

 - will not generate code for boundary value checking, when switch statements
 are turned into jump-tables (dangerous).
 For more details see section 
\begin_inset LatexCommand \ref{sub:'switch'-Statements}

\end_inset

.
\end_layout

\begin_layout Itemize

\series bold
noloopreverse
\series default

\begin_inset LatexCommand \index{\#pragma noloopreverse}

\end_inset

 - Will not do loop reversal optimization
\end_layout

\begin_layout Itemize

\series bold
nooverlay
\series default

\begin_inset LatexCommand \index{\#pragma nooverlay}

\end_inset

 - the compiler will not overlay the parameters and local variables of a
 function.
\end_layout

\begin_layout Itemize

\series bold
stackauto
\series default

\begin_inset LatexCommand \index{\#pragma stackauto}

\end_inset

- See option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset

 and section 
\begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}

\end_inset

 Parameters and Local Variables.
\end_layout

\begin_layout Itemize

\series bold
opt_code_speed
\series default
 
\begin_inset LatexCommand \index{\#pragma opt\_code\_speed}

\end_inset

- The compiler will optimize code generation towards fast code, possibly
 at the expense of code size.
 Currently this has little effect.
\end_layout

\begin_layout Itemize

\series bold
opt_code_size
\series default
 
\begin_inset LatexCommand \index{\#pragma opt\_code\_size}

\end_inset

- The compiler will optimize code generation towards compact code, possibly
 at the expense of code speed.
 Currently this has little effect.
\end_layout

\begin_layout Itemize

\series bold
opt_code_balanced
\series default
 
\begin_inset LatexCommand \index{\#pragma opt\_code\_balanced}

\end_inset

- The compiler will attempt to generate code that is both compact and fast,
 as long as meeting one goal is not a detriment to the other (this is the
 default).
 
\end_layout

\begin_layout Itemize

\series bold
std_sdcc89
\series default
 
\begin_inset LatexCommand \index{\#pragma std\_sdcc89}

\end_inset

- Generally follow the C89 standard, but allow SDCC features that conflict
 with the standard (default).
\end_layout

\begin_layout Itemize

\series bold
std_c89
\series default
 
\begin_inset LatexCommand \index{\#pragma std\_c89}

\end_inset

- Follow the C89 standard and disable SDCC features that conflict with the
 standard.
\end_layout

\begin_layout Itemize

\series bold
std_sdcc99
\series default
 
\begin_inset LatexCommand \index{\#pragma std\_sdcc99}

\end_inset

- Generally follow the C99 standard, but allow SDCC features that conflict
 with the standard (incomplete support).
\end_layout

\begin_layout Itemize

\series bold
std_c99
\series default
 
\begin_inset LatexCommand \index{\#pragma std\_c99}

\end_inset

- Follow the C99 standard and disable SDCC features that conflict with the
 standard (incomplete support).
\end_layout

\begin_layout Itemize

\series bold
codeseg
\series default
 <name>
\begin_inset LatexCommand \index{\#pragma codeseg}

\end_inset

- Use this name (max.
 8 characters) for the code segment.
 See option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-codeseg.
\end_layout

\begin_layout Itemize

\series bold
constseg
\series default
 <name>
\begin_inset LatexCommand \index{\#pragma constseg}

\end_inset

- Use this name (max.
 8 characters) for the const segment.
 See option -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-constseg.
\end_layout

\begin_layout Standard
The preprocessor SDCPP
\begin_inset LatexCommand \index{sdcpp (preprocessor)}

\end_inset

 supports the following #pragma directives:
\end_layout

\begin_layout Itemize

\series bold
pedantic_parse_number
\series default

\begin_inset LatexCommand \index{pedantic}

\end_inset


\begin_inset LatexCommand \index{\#pragma pedantic\_parse\_number}

\end_inset

 (+ | -) 
\begin_inset LatexCommand \label{ite:pedantic_parse_number}

\end_inset

- Pedantic parse numbers so that situations like 0xfe-LO_B(3) are parsed
 properly and the macro LO_B(3) gets expanded.
 Default is off.
 See also the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-pedantic-parse-number command line option 
\begin_inset LatexCommand \vpageref{lyx:-pedantic-parse-number}

\end_inset

.
 
\newline
Below is an example on how to use this pragma.

\emph on
 Note: this functionality is not in conformance with standard!
\end_layout

\begin_layout Verse

\family typewriter
#pragma pedantic_parse_number +
\begin_inset LatexCommand \index{\#pragma pedantic\_parse\_number}

\end_inset


\newline

\newline
#define LO_B(x) ((x) & 0xff)
\newline

\newline
unsigned char foo(void)
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
unsigned char c=0xfe-LO_B(3)
;
\newline

\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
return c;
\newline
}
\newline

\end_layout

\begin_layout Itemize

\series bold
preproc_asm
\series default

\begin_inset LatexCommand \index{\#pragma preproc\_asm}

\end_inset

 (+ | -) - switch _asm _endasm block preprocessing on / off.
 Default is on.
 You use this prama to define multilines of assembly code.
 This will prevent the preprocessor from changing the formating required
 by assembly code.
 Below is an example on how to use this pragma.
\end_layout

\begin_layout Verse

\family typewriter
#pragma preproc_asm -
\begin_inset LatexCommand \index{\#pragma preproc\_asm}

\end_inset


\newline
#define MYDELAY _asm
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
nop ;my assembly comment...
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
nop
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
nop
\newline
_endasm
\newline
#pragma preproc_asm
 +
\newline

\newline
void foo (void) 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 MYDELAY;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 ...
 
\newline
} 
\newline

\end_layout

\begin_layout Itemize

\series bold
sdcc_hash
\series default

\begin_inset LatexCommand \index{\#pragma sdcc\_hash}

\end_inset

 (+ | -) - Allow "naked" hash in macro definition, for example:
\newline

\family typewriter
#define DIR_LO(x) #(x & 0xff)
\family default

\newline
Default is off.
 Below is an example on how to use this pragma.
\end_layout

\begin_layout Verse

\family typewriter
#pragma preproc_asm +
\newline
#pragma sdcc_hash +
\begin_inset LatexCommand \index{\#pragma sdcc\_hash}

\end_inset


\newline

\newline
#define ROMCALL(x) 
\backslash

\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov R6_B3, #(x & 0xff) 
\backslash

\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mov R7_B3, #((x >> 8) & 0xff) 
\backslash

\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
lcall __romcall
\newline

\newline
...
\newline
_asm
\newline
ROMCALL(72)
\newline
_endasm;
\newline
...
\newline

\end_layout

\begin_layout Standard
Some of the pragmas are intended to be used to turn-on or off certain optimizati
ons which might cause the compiler to generate extra stack and/or data space
 to store compiler generated temporary variables.
 This usually happens in large functions.
 Pragma directives should be used as shown in the following example, they
 are used to control options and optimizations for a given function.
 
\end_layout

\begin_layout Verse

\family typewriter
#pragma save
\begin_inset LatexCommand \index{\#pragma save}

\end_inset

 \InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* save the current settings */ 
\newline
#pragma nogcse
\begin_inset LatexCommand \index{\#pragma nogcse}

\end_inset

 \InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* turnoff global subexpression elimination */ 
\newline
#pragma noinduction
\begin_inset LatexCommand \index{\#pragma noinduction}

\end_inset

 /* turn off induction optimizations */ 
\newline
int foo () 
\newline
{ 
\newline
\InsetSpace ~
 \InsetSpace ~
 ...
 
\newline
\InsetSpace ~
 \InsetSpace ~
 /* large code */ 
\newline
\InsetSpace ~
 \InsetSpace ~
 ...
 
\newline
} 
\newline
#pragma restore
\begin_inset LatexCommand \index{\#pragma restore}

\end_inset

 /* turn the optimizations back on */
\end_layout

\begin_layout Standard
The compiler will generate a warning message when extra space is allocated.
 It is strongly recommended that the save and restore pragmas be used when
 changing options for a function.
\newline

\newline

\newline

\end_layout

\begin_layout Section
Defines Created by the Compiler
\end_layout

\begin_layout Standard
The compiler creates the following #defines
\begin_inset LatexCommand \index{\#defines}

\end_inset


\begin_inset LatexCommand \index{Defines created by the compiler}

\end_inset

:
\newline

\end_layout

\begin_layout Standard
\begin_inset Tabular
<lyxtabular version="3" rows="15" columns="2">
<features>
<column alignment="left" valignment="top" leftline="true" width="3in">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="3in">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
#define
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Description
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC
\begin_inset LatexCommand \index{SDCC}

\end_inset

 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Always defined.
 Since version 2.5.6 the version number as an int (ex.
 256)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_mcs51
\begin_inset LatexCommand \index{SDCC\_mcs51}

\end_inset

 or SDCC_ds390
\begin_inset LatexCommand \index{SDCC\_ds390}

\end_inset

 or SDCC_z80
\begin_inset LatexCommand \index{SDCC\_z80}

\end_inset

, etc.
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
depending on the model used (e.g.: -mds390)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
__mcs51
\begin_inset LatexCommand \index{\_\_mcs51}

\end_inset

, __ds390
\begin_inset LatexCommand \index{\_\_ds390}

\end_inset

, __hc08
\begin_inset LatexCommand \index{\_\_hc08}

\end_inset

, __z80
\begin_inset LatexCommand \index{\_\_z80}

\end_inset

, etc
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
depending on the model used (e.g.
 -mz80)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_STACK_AUTO
\begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\emph default
 option is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_MODEL_SMALL
\begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-small
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_MODEL_MEDIUM
\begin_inset LatexCommand \index{SDCC\_MODEL\_MEDIUM}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-medium
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_MODEL_LARGE
\begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-model-large
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_USE_XSTACK
\begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-xstack
\emph default
 option is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_STACK_TENBIT
\begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}

\end_inset

 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-mds390
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_MODEL_FLAT24
\begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-mds390
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_REVISION
\begin_inset LatexCommand \index{SDCC\_REVISION}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Always defined.
 SDCC svn revision number
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_PARMS_IN_BANK1
\begin_inset LatexCommand \index{SDCC\_PARMS\_IN\_BANK1}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-parms-in-bank1
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_FLOAT_REENT
\begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-float-reent
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_INT_LONG_REENT
\begin_inset LatexCommand \index{SDCC\_INT\_LONG\_REENT}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
when 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-int-long-reent
\emph default
 is used
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Chapter
Notes on supported Processors
\end_layout

\begin_layout Section
MCS51 variants
\begin_inset LatexCommand \label{sub:MCS51-variants}

\end_inset


\begin_inset LatexCommand \index{MCS51 variants}

\end_inset


\end_layout

\begin_layout Standard
MCS51 processors are available from many vendors and come in many different
 flavours.
 While they might differ considerably in respect to Special Function Registers
 the core MCS51 is usually not modified or is kept compatible.
 
\end_layout

\begin_layout Subsection
pdata access by SFR 
\end_layout

\begin_layout Standard
With the upcome of devices with internal xdata and flash memory devices
 using port P2
\begin_inset LatexCommand \index{P2 (mcs51 sfr)}

\end_inset

 as dedicated I/O port is becoming more popular.
 Switching the high byte for pdata
\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}

\end_inset

 access which was formerly done by port P2 is then achieved by a Special
 Function Register
\begin_inset LatexCommand \index{sfr}

\end_inset

.
 In well-established MCS51 tradition the address of this 
\emph on
sfr
\emph default
 is where the chip designers decided to put it.
 Needless to say that they didn't agree on a common name either.
 So that the startup code can correctly initialize xdata variables, you
 should define an sfr with the name _XPAGE
\family typewriter

\begin_inset LatexCommand \index{\_XPAGE (mcs51)}

\end_inset


\family default
 at the appropriate location if the default, port P2, is not used for this.
 Some examples are:
\end_layout

\begin_layout Verse

\family typewriter
__sfr __at (0x85) _XPAGE; /* Ramtron VRS51 family a.k.a.
 MPAGE */
\end_layout

\begin_layout Verse

\family typewriter
__sfr __at (0x92) _XPAGE; /* Cypress EZ-USB family, Texas Instruments (Chipcon)
 a.k.a.
 MPAGE */
\end_layout

\begin_layout Verse

\family typewriter
__sfr __at (0x91) _XPAGE; /* Infineon (Siemens) C500 family a.k.a.
 XPAGE */
\end_layout

\begin_layout Verse

\family typewriter
__sfr __at (0xaf) _XPAGE; /* some Silicon Labs (Cygnal) chips a.k.a.
 EMI0CN */
\end_layout

\begin_layout Verse

\family typewriter
__sfr __at (0xaa) _XPAGE; /* some Silicon Labs (Cygnal) chips a.k.a.
 EMI0CN */
\end_layout

\begin_layout Standard
For more exotic implementations further customizations may be needed.
 See section 
\begin_inset LatexCommand \ref{sub:Startup-Code}

\end_inset

 for other possibilities.
\end_layout

\begin_layout Subsection
Other Features available by SFR
\end_layout

\begin_layout Standard
Some MCS51 variants offer features like Double DPTR
\begin_inset LatexCommand \index{DPTR}

\end_inset

, multiple DPTR, decrementing DPTR, 16x16 Multiply.
 These are currently not used for the MCS51 port.
 If you absolutely need them you can fall back to inline assembly or submit
 a patch to SDCC.
\end_layout

\begin_layout Subsection
Bankswitching
\end_layout

\begin_layout Standard
Bankswitching
\begin_inset LatexCommand \index{Bankswitching}

\end_inset

 (a.k.a.
 code banking
\begin_inset LatexCommand \index{code banking}

\end_inset

) is a technique to increase the code space above the 64k limit of the 8051.
\end_layout

\begin_layout Subsubsection
Hardware
\end_layout

\begin_layout Standard
\begin_inset Tabular
<lyxtabular version="3" rows="3" columns="4">
<features>
<column alignment="center" valignment="top" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
\begin_inset Text

\begin_layout Standard
8000-FFFF
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
bank1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
bank2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
bank3
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
\begin_inset Text

\begin_layout Standard
0000-7FFF
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
common
\end_layout

\end_inset
</cell>
<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell multicolumn="2" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
</row>
<row>
<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
\begin_inset Text

\begin_layout Standard
SiLabs C8051F120 example
\end_layout

\end_inset
</cell>
<cell multicolumn="2" alignment="center" valignment="top" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell multicolumn="2" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell multicolumn="2" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\newline
Usually the hardware uses some sfr (an output port or an internal sfr) to
 select a bank and put it in the banked area of the memory map.
 The selected bank usually becomes active immediately upon assignment to
 this sfr and when running inside a bank it will switch out this code it
 is currently running.
 Therefor you cannot jump or call directly from one bank to another and
 need to use a so-called trampoline in the common area.
 For SDCC an example trampoline is in crtbank.asm and you may need to change
 it to your 8051 derivative or schematic.
 The presented code is written for the C8051F120.
\newline

\newline
When calling a banked function
 SDCC will put the LSB of the functions address in register R0, the MSB
 in R1 and the bank in R2 and then call this trampoline 
\emph on
__sdcc_banked_call
\emph default
.
 The current selected bank is saved on the stack, the new bank is selected
 and an indirect jump is made.
 When the banked function returns it jumps to 
\emph on
__sdcc_banked_ret
\emph default
 which restores the previous bank and returns to the caller.
\end_layout

\begin_layout Subsubsection
Software
\end_layout

\begin_layout Standard
When writing banked software using SDCC you need to use some special keywords
 and options.
 You also need to take over a bit of work from the linker.
\newline

\newline
To create a function
 that can be called from another bank it requires the keyword 
\emph on
banked
\emph default

\begin_inset LatexCommand \index{banked}

\end_inset

.
 The caller must see this in the prototype of the callee and the callee
 needs it for a proper return.
 Called functions within the same bank as the caller do not need the 
\emph on
banked
\emph default
 keyword nor do functions in the common area.
 Beware: SDCC does not know or check if functions are in the same bank.
 This is your responsibility!
\newline

\newline
Normally all functions you write end up in
 the segment CSEG.
 If you want a function explicitly to reside in the common area put it in
 segment HOME.
 This applies for instance to interrupt service routines as they should
 not be banked.
\end_layout

\begin_layout Standard
Functions that need to be in a switched bank must be put in a named segment.
 The name can be mostly anything upto eight characters (e.g.
 BANK1).
 To do this you either use -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-codeseg BANK1 (See 
\begin_inset LatexCommand \ref{lyx:-codeseg}

\end_inset

) on the command line when compiling or #pragma codeseg BANK1 (See 
\begin_inset LatexCommand \ref{sec:Pragmas}

\end_inset

) at the top of the C source file.
 The segment name always applies to the whole source file and generated
 object so functions for different banks need to be defined in different
 source files.
\newline

\newline
When linking your objects you need to tell the linker where
 to put your segments.
 To do this you use the following command line option to SDCC: -Wl-b BANK1=0x180
00 (See 
\begin_inset LatexCommand \ref{lyx:-Wl option}

\end_inset

).
 This sets the virtual start address of this segment.
 It sets the banknumber to 0x01 and maps the bank to 0x8000 and up.
 The linker will not check for overflows, again this is your responsibility.
\end_layout

\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
DS400 port
\end_layout

\begin_layout Standard
The DS80C400
\begin_inset LatexCommand \index{DS80C400}

\end_inset


\begin_inset LatexCommand \index{DS400}

\end_inset

 microcontroller has a rich set of peripherals.
 In its built-in ROM library it includes functions to access some of the
 features, among them is a TCP stack with IP4 and IP6 support.
 Library headers (currently in beta status) and other files are provided
 at 
\size footnotesize

\begin_inset LatexCommand \url{ftp://ftp.dalsemi.com/pub/tini/ds80c400/c_libraries/sdcc/index.html}

\end_inset

.
 
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
The Z80 and gbz80 port
\end_layout

\begin_layout Standard
SDCC can target both the Zilog Z80
\begin_inset LatexCommand \index{Z80}

\end_inset

 and the Nintendo Gameboy's Z80-like gbz80
\begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}

\end_inset

.
 The Z80 port is passed through the same 
\emph on
regressions tests
\begin_inset LatexCommand \index{Regression test}

\end_inset


\emph default
 (see section 
\begin_inset LatexCommand \ref{sec:Quality-control}

\end_inset

) as the MCS51 and DS390 ports, so floating point support, support for long
 variables and bitfield support is fine.
 See mailing lists and forums about interrupt routines.
\end_layout

\begin_layout Standard
As always, the code is the authoritative reference - see z80/ralloc.c and
 z80/gen.c.
 The stack
\begin_inset LatexCommand \index{Z80!stack}

\end_inset

 frame is similar to that generated by the IAR Z80 compiler.
 IX is used as the base pointer, HL and IY are used as a temporary registers,
 and BC and DE are available for holding variables.
 Return values
\begin_inset LatexCommand \index{Z80!return value}

\end_inset

 for the Z80 port are stored in L (one byte), HL (two bytes), or DEHL (four
 bytes).
 The gbz80 port use the same set of registers for the return values, but
 in a different order of significance: E (one byte), DE (two bytes), or
 HLDE (four bytes).
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
The HC08 port
\end_layout

\begin_layout Standard
The port to the Freescale/Motorola HC08
\begin_inset LatexCommand \index{HC08}

\end_inset

 family has been added in October 2003, and is still undergoing some basic
 development.
 The code generator is complete, but the register allocation is still quite
 unoptimized.
 Some of the SDCC's standard C library functions have embedded non-HC08
 inline assembly and so are not yet usable.
\end_layout

\begin_layout Standard
The HC08 port passes the regression test suite (see section 
\begin_inset LatexCommand \ref{sec:Quality-control}

\end_inset

).
\begin_inset VSpace bigskip
\end_inset


\end_layout

\begin_layout Section
The PIC14
\begin_inset LatexCommand \index{PIC14}

\end_inset

 port
\end_layout

\begin_layout Standard
The PIC14 port adds support for Microchip
\begin_inset LatexCommand \index{Microchip}

\end_inset


\begin_inset Formula $^{\text{TM}}$
\end_inset

 PIC
\begin_inset LatexCommand \index{PIC14}

\end_inset


\begin_inset Formula $^{\text{TM}}$
\end_inset

 MCUs with 14 bit wide instructions.
 This port is not yet mature and still lacks many features.
 However, it can work for simple code.
\end_layout

\begin_layout Standard
Currently supported devices include:
\end_layout

\begin_layout Standard
12F: 629, 635, 675, 683
\end_layout

\begin_layout Standard
16C: 432, 433
\end_layout

\begin_layout Standard
16C: 554, 557, 558
\end_layout

\begin_layout Standard
16C: 62, 620, 620a, 621, 621a, 622, 622a, 63a, 65b
\end_layout

\begin_layout Standard
16C: 71, 710, 711, 715, 717, 72, 73b, 745, 74b, 765, 770, 771, 773, 774,
 781, 782
\end_layout

\begin_layout Standard
16C: 925, 926
\end_layout

\begin_layout Standard
16CR: 620a, 73, 74, 76, 77
\end_layout

\begin_layout Standard
16F: 616, 627, 627a, 628, 628a, 630, 636, 639, 648, 648a, 676, 684, 685,
 687, 688, 689, 690
\end_layout

\begin_layout Standard
16F: 716, 72, 73, 737, 74, 747, 76, 767, 77, 777, 785
\end_layout

\begin_layout Standard
16F: 818, 819, 84, 84a, 87, 870, 871, 872, 873, 873a, 874, 874a, 876, 876a,
 877, 877a, 88, 886, 887
\end_layout

\begin_layout Standard
16F: 913, 914, 916, 917, 946
\end_layout

\begin_layout Standard
26HV: 626, 785
\end_layout

\begin_layout Standard
An up-to-date list of currently supported devices can be obtained via 
\family typewriter
sdcc -mpic14 -phelp foo.c
\family default
 (foo.c must exist...).
\end_layout

\begin_layout Subsection
PIC Code Pages
\begin_inset LatexCommand \index{code page (pic14)}

\end_inset

 and Memory Banks
\begin_inset LatexCommand \index{Memory bank (pic14)}

\end_inset


\end_layout

\begin_layout Standard
The linker organizes allocation for the code page and RAM banks.
 It does not have intimate knowledge of the code flow.
 It will put all the code section of a single .asm file into a single code
 page.
 In order to make use of multiple code pages, separate asm files must be
 used.
 The compiler assigns all 
\emph on
static
\emph default
 functions of a single .c file into the same code page.
\newline

\newline
To get the best results,
 follow these guidelines:
\end_layout

\begin_layout Enumerate
Make local functions static, as non static functions require code page selection
 overhead.
\newline
Due to the way sdcc handles functions, place called functions prior
 to calling functions in the file wherever possible: Otherwise sdcc will
 insert unneccessary pagesel directives around the call, believing that
 the called function is externally defined.
\end_layout

\begin_layout Enumerate
For devices that have multiple code pages it is more efficient to use the
 same number of files as pages: Use up to 4 separate .c files for the 16F877,
 but only 2 files for the 16F874.
 This way the linker can put the code for each file into different code
 pages and there will be less page selection overhead.
\end_layout

\begin_layout Enumerate
And as for any 8 bit micro (especially for PIC14 as they have a very simple
 instruction set), use `unsigned char' wherever possible instead of `int'.
\end_layout

\begin_layout Subsection
Adding New Devices to the Port 
\end_layout

\begin_layout Standard
Adding support for a new 14
\begin_inset ERT
status open

\begin_layout Standard


\backslash
,
\end_layout

\end_inset

bit PIC MCU requires the following steps:
\end_layout

\begin_layout Enumerate
Create a new device description.
\newline
Each device is described in two files: pic16f*.h
 and pic16f*.c.
 These files primarily define SFRs, structs to access their bits, and symbolic
 configuration options.
 Both files can be generated from gputils' .inc files using the perl script
 
\family typewriter
support/scripts/inc2h.pl
\family default
.
 This file also contains further instructions on how to proceed.
\end_layout

\begin_layout Enumerate
Copy the .h file into SDCC's include path and either add the .c file to your
 project or copy it to 
\family typewriter
device/lib/pic/libdev
\family default
.
 Afterwards, rebuild and install the libraries.
\end_layout

\begin_layout Enumerate
Edit pic14devices.txt in SDCC's include path (
\family typewriter
device/include/pic/
\family default
 in the source tree or 
\family typewriter
/usr/local/share/sdcc/include/pic
\family default
 after installation).
\newline
You need to add a device specification here to make
 the memory layout (code banks, RAM, aliased memory regions, ...) known to
 the compiler.
 Probably you can copy and modify an existing entry.
 The file format is documented at the top of the file.
\end_layout

\begin_layout Subsection
Interrupt Code
\end_layout

\begin_layout Standard
For the interrupt function, use the keyword `__interrupt'
\begin_inset LatexCommand \index{PIC14!interrupt}

\end_inset

 with level number of 0 (PIC14 only has 1 interrupt so this number is only
 there to avoid a syntax error - it ought to be fixed).
 E.g.:
\end_layout

\begin_layout Verse

\family typewriter
void Intr(void) __interrupt 0
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
T0IF = 0; /* Clear timer interrupt */
\newline
}
\end_layout

\begin_layout Subsection
Linking and Assembling
\end_layout

\begin_layout Standard
For assembling you can use either GPUTILS'
\begin_inset LatexCommand \index{gputils (pic tools)}

\end_inset

 gpasm.exe or MPLAB's mpasmwin.exe.
 GPUTILS are available from 
\begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}

\end_inset

.
 For linking you can use either GPUTILS' gplink or MPLAB's mplink.exe.
 If you use MPLAB and an interrupt function then the linker script file
 vectors section will need to be enlarged to link with mplink.
\newline

\newline
Here is a 
\family typewriter
Makefile
\family default
 using GPUTILS:
\end_layout

\begin_layout Verse

\family typewriter
.c.o:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcc -V -mpic14 -p16f877 -c $< 
\newline

\newline
$(PRJ).hex: $(OBJS) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
gplink -m -s $(PRJ).lkr
 -o $(PRJ).hex $(OBJS) libsdcc.lib
\end_layout

\begin_layout Standard
Here is a 
\family typewriter
Makefile
\family default
 using MPLAB:
\end_layout

\begin_layout Verse

\family typewriter
.c.o: 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcc -S -V -mpic14 -p16f877 $< 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mpasmwin /q /o $*.asm
\newline

\newline
$(PRJ).hex: $(OBJS)
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mplink /v $(PRJ).lkr /m $(PRJ).map /o $(PRJ).hex $(OBJS) libsdcc.lib
\end_layout

\begin_layout Standard
Please note that indentations within a
\family typewriter
 Makefile
\family default
 have to be done with a tabulator character.
\end_layout

\begin_layout Subsection
Command-Line Options
\end_layout

\begin_layout Standard
Besides the switches common to all SDCC backends, the PIC14 port accepts
 the following options (for an updated list see sdcc -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-help):
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug-xtra
\begin_inset LatexCommand \index{PIC14!Options!-\/-debug-extra}

\end_inset

 emit debug info in assembly output
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-pcode-opt
\begin_inset LatexCommand \index{PIC14!Options!-\/-no-pcode-opt}

\end_inset

 disable (slightly faulty) optimization on pCode
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-loc
\begin_inset LatexCommand \index{PIC14!Options!-\/-stack-loc}

\end_inset

 sets the lowest address of the argument passing stack (defaults to a suitably
 large shared databank to reduce BANKSEL overhead)
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-size
\begin_inset LatexCommand \index{PIC14!Options!-\/-stack-size}

\end_inset

 sets the size if the argument passing stack (default: 16, minimum: 4)
\end_layout

\begin_layout Subsection
Environment Variables
\end_layout

\begin_layout Standard
The PIC14 port recognizes the following environment variables:
\end_layout

\begin_layout Description
SDCC_PIC14_SPLIT_LOCALS If set and not empty, sdcc will allocate each temporary
 register (the ones called r0xNNNN) in a section of its own.
 By default (if this variable is unset), sdcc tries to cluster registers
 in sections in order to reduce the BANKSEL overhead when accessing them.
\end_layout

\begin_layout Subsection
The Library
\end_layout

\begin_layout Standard
The PIC14 library currently only contains support routines required by the
 compiler to implement multiplication, division, and floating point support.
 No libc-like replacement is available at the moment, though many of the
 common sdcc library sources (in 
\family typewriter
device/lib
\family default
) should also compile with the PIC14 port.
\end_layout

\begin_layout Subsubsection
error: missing definition for symbol ``__gptrget1''
\end_layout

\begin_layout Standard
The PIC14 port uses library routines to provide more complex operations
 like multiplication, division/modulus and (generic) pointer dereferencing.
 In order to add these routines to your project, you must link with PIC14's
 
\family typewriter
libsdcc.lib
\family default
.
 For single source file projects this is done automatically, more complex
 projects must add 
\family typewriter
libsdcc.lib
\family default
 to the linker's arguments.
 Make sure you also add an include path for the library (using the -I switch
 to the linker)!
\end_layout

\begin_layout Subsubsection
Processor mismatch in file ``XXX''.
\end_layout

\begin_layout Standard
This warning can usually be ignored due to the very good compatibility amongst
 14
\begin_inset ERT
status open

\begin_layout Standard


\backslash
,
\end_layout

\end_inset

bit PIC
\begin_inset LatexCommand \index{PIC14}

\end_inset

 devices.
\end_layout

\begin_layout Standard
You might also consider recompiling the library for your specific device
 by changing the ARCH=p16f877 (default target) entry in 
\family typewriter
device/lib/pic/Makefile.in
\family default
 and 
\family typewriter
device/lib/pic/Makefile
\family default
 to reflect your device.
 This might even improve performance for smaller devices as unneccesary
 BANKSELs might be removed.
\end_layout

\begin_layout Subsection
Known Bugs
\end_layout

\begin_layout Subsubsection
Function arguments
\end_layout

\begin_layout Standard
Functions with variable argument lists (like printf) are not yet supported.
 Similarly, taking the address of the first argument passed into a function
 does not work: It is currently passed in WREG and has no address...
\end_layout

\begin_layout Subsubsection
Regression tests fail
\end_layout

\begin_layout Standard
Though the small subset of regression tests in src/regression passes, SDCC
 regression test suite does not, indicating that there are still major bugs
 in the port.
 However, many smaller projects have successfully used SDCC in the past...
\end_layout

\begin_layout Standard

\size footnotesize

\newpage

\end_layout

\begin_layout Section
The PIC16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port
\end_layout

\begin_layout Standard
The PIC16 port adds support for Microchip
\begin_inset LatexCommand \index{Microchip}

\end_inset


\begin_inset Formula $^{\text{TM}}$
\end_inset

 PIC
\begin_inset LatexCommand \index{PIC}

\end_inset


\begin_inset Formula $^{\text{TM}}$
\end_inset

 MCUs with 16 bit wide instructions.
 Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx
; devices supported by the port include:
\end_layout

\begin_layout Standard
18F: 242, 248, 252, 258, 442, 448, 452, 458
\end_layout

\begin_layout Standard
18F: 1220, 1320
\end_layout

\begin_layout Standard
18F: 2220, 2221, 2320, 2321, 2331, 2420, 2423, 2431, 2455, 2480, 24j10
\end_layout

\begin_layout Standard
18F: 2520, 2523, 2525, 2550, 2580, 2585, 25j10, 2620, 2680, 2682, 2685
\end_layout

\begin_layout Standard
18F: 4220, 4221, 4320, 4321, 4331, 4420, 4423, 4431, 4455, 4480, 44j10
\end_layout

\begin_layout Standard
18F: 4520, 4523, 4525, 4550, 4580, 4585, 45j10, 4620, 4680, 4682, 4685
\end_layout

\begin_layout Standard
18F: 6520, 6585, 6620, 6680, 6720
\end_layout

\begin_layout Standard
18F: 8520, 8585, 8620, 8680, 8720
\end_layout

\begin_layout Standard
A list of supported devices is also available via '
\family typewriter
sdcc -mpic16 -plist
\family default
'.
\end_layout

\begin_layout Subsection
Global Options
\end_layout

\begin_layout Standard
PIC16 port supports the standard command line arguments as supposed, with
 the exception of certain cases that will be mentioned in the following
 list:
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-callee-saves
\begin_inset LatexCommand \index{PIC16!Options!-\/-callee-saves}

\end_inset

 See -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-all-callee-saves
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-fommit-frame-pointer
\begin_inset LatexCommand \index{PIC16!Options!-\/-fommit-frame-pointer}

\end_inset

 Frame pointer will be omitted when the function uses no local variables.
\end_layout

\begin_layout Subsection
Port Specific Options
\begin_inset LatexCommand \index{Options PIC16}

\end_inset


\end_layout

\begin_layout Standard
The port specific options appear after the global options in the sdcc -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-help output.
\end_layout

\begin_layout Subsubsection
Code Generation Options
\end_layout

\begin_layout Standard
These options influence the generated assembler code.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-pstack-model=[model] Used in conjuction with the command above.
 Defines the stack model to be used, valid stack models are:
\end_layout

\begin_deeper
\begin_layout List
\labelwidthstring 00.00.0000

\emph on
small
\emph default
 Selects small stack model.
 8 bit stack and frame pointers.
 Supports 256 bytes stack size.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\emph on
large
\emph default
 Selects large stack model.
 16 bit stack and frame pointers.
 Supports 65536 bytes stack size.
\end_layout

\end_deeper
\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-pno-banksel Do not generate BANKSEL assembler directives.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-extended Enable extended instruction set/literal offset addressing mode.
 Use with care!
\end_layout

\begin_layout Subsubsection
Optimization Options
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-obanksel=n Set optimization level for inserting BANKSELs.
\newline

\end_layout

\begin_deeper
\begin_layout List
\labelwidthstring 00.00.0000
0 no optimization
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
1 checks previous used register and if it is the same then does not emit
 BANKSEL, accounts only for labels.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
2 tries to check the location of (even different) symbols and removes BANKSELs
 if they are in the same bank.
 
\newline

\emph on
Important: There might be problems if the linker script has data sections
 across bank borders!
\end_layout

\end_deeper
\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-denable-peeps Force the usage of peepholes.
 Use with care.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-optimize-goto Try to use (conditional) BRA instead of GOTO.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-optimize-cmp Try to optimize some compares.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-optimize-df Analyze the dataflow of the generated code and improve it.
\end_layout

\begin_layout Subsubsection
Assembling Options
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-asm= Sets the full path and name of an external assembler to call.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-mplab-comp MPLAB
\begin_inset LatexCommand \index{PIC16!MPLAB}

\end_inset

 compatibility option.
 Currently only suppresses special gpasm directives.
\end_layout

\begin_layout Subsubsection
Linking Options
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-link= Sets the full path and name of an external linker to call.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-preplace-udata-with=[kword] Replaces the default udata keyword for allocating
 unitialized data variables with [kword].
 Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-ivt-loc=n Place the interrupt vector table at address 
\emph on
n
\emph default
.
 Useful for bootloaders.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-nodefaultlibs Do not link default libraries when linking.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-use-crt= Use a custom run-time module instead of the defaults.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-no-crt Don't link the default run-time modules
\end_layout

\begin_layout Subsubsection
Debugging Options
\end_layout

\begin_layout Standard
Debugging options enable extra debugging information in the output files.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug-xtra Similar to -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug
\begin_inset LatexCommand \index{-\/-debug}

\end_inset

, but dumps more information.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug-ralloc Force register allocator to dump <source>.d file with debugging
 information.
 <source> is the name of the file being compiled.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-pcode-verbose Enable pcode debugging information in translation.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-calltree Dump call tree in .calltree file.
\end_layout

\begin_layout Description
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-gstack Trace push/pops for stack pointer overflow.
\end_layout

\begin_layout Subsection
Enviroment Variables
\end_layout

\begin_layout Standard
There is a number of enviromental variables that can be used when running
 SDCC to enable certain optimizations or force a specific program behaviour.
 these variables are primarily for debugging purposes so they can be enabled/dis
abled at will.
\end_layout

\begin_layout Standard
Currently there is only two such variables available:
\end_layout

\begin_layout Description
OPTIMIZE_BITFIELD_POINTER_GET When this variable exists, reading of structure
 bitfields is optimized by directly loading FSR0 with the address of the
 bitfield structure.
 Normally SDCC will cast the bitfield structure to a bitfield pointer and
 then load FSR0.
 This step saves data ram and code space for functions that make heavy use
 of bitfields.
 (i.e., 80 bytes of code space are saved when compiling malloc.c with this
 option).
 
\end_layout

\begin_layout Description
NO_REG_OPT Do not perform pCode registers optimization.
 This should be used for debugging purposes.
 If bugs in the pcode optimizer are found, users can benefit from temporarily
 disabling the optimizer until the bug is fixed.
\end_layout

\begin_layout Subsection
Preprocessor Macros
\end_layout

\begin_layout Standard
PIC16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port defines the following preprocessor macros while translating a source.
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="2">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Macro
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Description
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_pic16
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Port identification
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

_pic16
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Port identification (same as above)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
pic18fxxxx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
MCU Identification.
 
\emph on
xxxx
\emph default
 is the microcontrol identification number, i.e.
 452, 6620, etc
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
_
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

_18Fxxxx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
MCU Identification (same as above)
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
STACK_MODEL_nnn
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
nnn = SMALL or LARGE respectively according to the stack model used
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
In addition the following macros are defined when calling assembler:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="2">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Macro
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Description
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
__18Fxxxx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
MCU Identification.
 
\emph on
xxxx
\emph default
 is the microcontrol identification number, i.e.
 452, 6620, etc
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC_MODEL_nnn
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
nnn = SMALL or LARGE respectively according to the memory model used for
 SDCC
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
STACK_MODEL_nnn
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
nnn = SMALL or LARGE respectively according to the stack model used
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Subsection
Directories
\end_layout

\begin_layout Standard
PIC16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port uses the following directories for searching header files and libraries.
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="3" columns="4">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="center" valignment="top" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Directory
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Description
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Target
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Command prefix
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PREFIX/sdcc/include/pic16
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PIC16 specific headers
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Compiler
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-I
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PREFIX/sdcc/lib/pic16
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PIC16 specific libraries
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Linker
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
-L
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Subsection
Pragmas
\begin_inset LatexCommand \label{sub:PIC16_Pragmas}

\end_inset


\end_layout

\begin_layout Standard
The PIC16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port currently supports the following pragmas:
\end_layout

\begin_layout Description
stack
\begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma stack}

\end_inset

 This forces the code generator to initialize the stack & frame pointers
 at a specific address.
 This is an ad hoc solution for cases where no STACK directive is available
 in the linker script or gplink is not instructed to create a stack section.
\newline
The
 stack pragma should be used only once in a project.
 Multiple pragmas may result in indeterminate behaviour of the program.
\begin_inset Foot
status open

\begin_layout Standard
The old format (ie.
 #pragma stack 0x5ff) is deprecated and will cause the stack pointer to
 cross page boundaries (or even exceed the available data RAM) and crash
 the program.
 Make sure that stack does not cross page boundaries when using the SMALL
 stack model.
\end_layout

\end_inset


\newline
The format is as follows:
\newline

\end_layout

\begin_layout LyX-Code
#pragma stack bottom_address [stack_size]
\newline

\end_layout

\begin_layout Standard

\emph on
bottom_address
\emph default
 is the lower bound of the stack section.
 The stack pointer initially will point at address (bottom_address+stack_size-1).
\end_layout

\begin_layout LyX-Code
Example:
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
/* initializes stack of 100 bytes at RAM address 0x200 */
\end_layout

\begin_layout LyX-Code
#pragma stack 0x200 100
\end_layout

\begin_layout Standard
If the stack_size field is omitted then a stack is created with the default
 size of 64.
 This size might be enough for most programs, but its not enough for operations
 with deep function nesting or excessive stack usage.
\end_layout

\begin_layout Description
code
\begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma code}

\end_inset

 Force a function to a static FLASH address.
\end_layout

\begin_layout LyX-Code
Example:
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
/* place function test_func at 0x4000 */
\end_layout

\begin_layout LyX-Code
#pragma code test_func 0x4000
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout Description
library instructs the linker to use a library module.
\newline
Usage:
\end_layout

\begin_layout LyX-Code
#pragma library module_name
\end_layout

\begin_layout Standard

\emph on
module_name
\emph default
 can be any library or object file (including its path).
 Note that there are four reserved keywords which have special meaning.
 These are:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="3">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="block" valignment="top" leftline="true" width="20page%">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Keyword
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Description
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Module to link
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
ignore
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
ignore all library pragmas
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
(none)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
link the C library
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
libc18f
\emph default
.lib
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
math
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
link the Math libarary
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
libm18f
\emph default
.lib
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
io
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
link the I/O library
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
libio18f*
\emph default
.lib
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
debug
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
link the debug library
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
libdebug
\emph default
.lib
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline
* is the device number, i.e.
 452 for PIC18F452 MCU.
\end_layout

\begin_layout Standard
This feature allows for linking with specific libraries withoug having to
 explicit name them in the command line.
 Note that the 
\noun on
ignore
\noun default
 keyword will reject all modules specified by the library pragma.
\end_layout

\begin_layout Description
udata The pragma udata instructs the compiler to emit code so that linker
 will place a variable at a specific memory bank.
\end_layout

\begin_layout LyX-Code
Example:
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
/* places variable foo at bank2 */
\end_layout

\begin_layout LyX-Code
#pragma udata bank2 foo
\end_layout

\begin_layout LyX-Code
char foo;
\end_layout

\begin_layout Standard
In order for this pragma to work extra SECTION directives should be added
 in the .lkr script.
 In the following example a sample .lkr file is shown:
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
// Sample linker script for the PIC18F452 processor
\end_layout

\begin_layout LyX-Code
LIBPATH .
\end_layout

\begin_layout LyX-Code
CODEPAGE   NAME=vectors    START=0x0            END=0x29           PROTECTED
\end_layout

\begin_layout LyX-Code
CODEPAGE   NAME=page       START=0x2A           END=0x7FFF
\end_layout

\begin_layout LyX-Code
CODEPAGE   NAME=idlocs     START=0x200000       END=0x200007       PROTECTED
\end_layout

\begin_layout LyX-Code
CODEPAGE   NAME=config     START=0x300000       END=0x30000D       PROTECTED
\end_layout

\begin_layout LyX-Code
CODEPAGE   NAME=devid      START=0x3FFFFE       END=0x3FFFFF       PROTECTED
\end_layout

\begin_layout LyX-Code
CODEPAGE   NAME=eedata     START=0xF00000       END=0xF000FF       PROTECTED
\end_layout

\begin_layout LyX-Code
ACCESSBANK NAME=accessram  START=0x0            END=0x7F
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
DATABANK   NAME=gpr0       START=0x80           END=0xFF
\end_layout

\begin_layout LyX-Code
DATABANK   NAME=gpr1       START=0x100          END=0x1FF
\end_layout

\begin_layout LyX-Code
DATABANK   NAME=gpr2       START=0x200          END=0x2FF
\end_layout

\begin_layout LyX-Code
DATABANK   NAME=gpr3       START=0x300          END=0x3FF
\end_layout

\begin_layout LyX-Code
DATABANK   NAME=gpr4       START=0x400          END=0x4FF
\end_layout

\begin_layout LyX-Code
DATABANK   NAME=gpr5       START=0x500          END=0x5FF
\end_layout

\begin_layout LyX-Code
ACCESSBANK NAME=accesssfr  START=0xF80          END=0xFFF          PROTECTED
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
SECTION    NAME=CONFIG     ROM=config
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
SECTION    NAME=bank0      RAM=gpr0       # these SECTION directives
\end_layout

\begin_layout LyX-Code
SECTION    NAME=bank1      RAM=gpr1       # should be added to link
\end_layout

\begin_layout LyX-Code
SECTION    NAME=bank2      RAM=gpr2       # section name 'bank?' with
\end_layout

\begin_layout LyX-Code
SECTION    NAME=bank3      RAM=gpr3       # a specific DATABANK name
\end_layout

\begin_layout LyX-Code
SECTION    NAME=bank4      RAM=gpr4
\end_layout

\begin_layout LyX-Code
SECTION    NAME=bank5      RAM=gpr5
\end_layout

\begin_layout Standard
The linker will recognise the section name set in the pragma statement and
 will position the variable at the memory bank set with the RAM field at
 the SECTION line in the linker script file.
\end_layout

\begin_layout Subsection
Header Files
\begin_inset LatexCommand \label{sub:PIC16_Header-Files}

\end_inset


\end_layout

\begin_layout Standard
There is one main header file
\begin_inset LatexCommand \index{PIC16!Header files}

\end_inset

 that can be included to the source files using the pic16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port.
 That file is the 
\series bold
pic18fregs.h
\series default
.
 This header file contains the definitions for the processor special registers,
 so it is necessary if the source accesses them.
 It can be included by adding the following line in the beginning of the
 file:
\end_layout

\begin_layout LyX-Code
#include <pic18fregs.h>
\end_layout

\begin_layout Standard
The specific microcontroller is selected within the pic18fregs.h automatically,
 so the same source can be used with a variety of devices.
\end_layout

\begin_layout Subsection
Libraries
\end_layout

\begin_layout Standard
The libraries
\begin_inset LatexCommand \index{PIC16!Libraries}

\end_inset

 that PIC16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port depends on are the microcontroller device libraries which contain
 the symbol definitions for the microcontroller special function registers.
 These libraries have the format pic18fxxxx.lib, where 
\emph on
xxxx
\emph default
 is the microcontroller identification number.
 The specific library is selected automatically by the compiler at link
 stage according to the selected device.
\end_layout

\begin_layout Standard
Libraries are created with gplib which is part of the gputils package 
\begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}

\end_inset

.
\end_layout

\begin_layout Subsubsection*
Building the libraries
\end_layout

\begin_layout Standard
Before using SDCC/pic16 there are some libraries that need to be compiled.
 This process is not done automatically by SDCC since not all users use
 SDCC for pic16 projects.
 So each user should compile the libraries separately.
\end_layout

\begin_layout Standard
The steps to compile the pic16 libraries under Linux and Mac OS X are:
\end_layout

\begin_layout LyX-Code
cd device/lib/pic16
\end_layout

\begin_layout LyX-Code
./configure
\end_layout

\begin_layout LyX-Code
make
\end_layout

\begin_layout LyX-Code
cd ..
\end_layout

\begin_layout LyX-Code
make model-pic16
\end_layout

\begin_layout LyX-Code
su -c 'make install'     # install the libraries, you need the root password
\end_layout

\begin_layout Standard
If you need to install the headers too, do:
\end_layout

\begin_layout LyX-Code
cd device/include
\end_layout

\begin_layout LyX-Code
su -c 'make install'     # install the headers, you need the root password
\end_layout

\begin_layout Standard
There exist a special target to build the I/O libraries.
 This target is not automatically build because it will build the I/O library
 for 
\emph on
every
\emph default
 supported device.
 This way building will take quite a lot of time.
 Users are advised to edit the 
\series bold
device/lib/pic16/pics.build
\series default
 file and then execute:
\end_layout

\begin_layout LyX-Code
make lib-io
\end_layout

\begin_layout Subsection
Adding New Devices to the Port
\end_layout

\begin_layout Standard
Adding support for a new 16
\begin_inset ERT
status open

\begin_layout Standard


\backslash
,
\end_layout

\end_inset

bit PIC MCU requires the following steps:
\end_layout

\begin_layout Enumerate
Create picDEVICE.c and picDEVICE.h from pDEVICE.inc using
\newline

\family typewriter
perl /path/to/sdcc/support/scripts/inc2h-pic16.pl /path/to/gputils/header/pDEVICE.
inc
\end_layout

\begin_layout Enumerate

\family typewriter
mv picDEVICE.h /path/to/sdcc/device/include/pic16
\end_layout

\begin_layout Enumerate

\family typewriter
mv picDEVICE.c /path/to/sdcc/device/lib/pic16/libdev
\end_layout

\begin_layout Enumerate
Add DEVICE to 
\family typewriter
/path/to/sdcc/device/lib/pic16/pics.all
\family default
 (and 
\family typewriter
.build
\family default
).
\newline
Note: No 18f prefix here!
\end_layout

\begin_layout Enumerate
Set up the I/O library by doing 
\series bold
one
\series default
 of the following:
\end_layout

\begin_deeper
\begin_layout Enumerate
Adjust 
\family typewriter
/path/to/sdcc/device/lib/pic16/libio/*.ignore
\family default

\newline
Add your DEVICE if it does not compile in 
\family typewriter
adc
\family default
, 
\family typewriter
i2c
\family default
, or 
\family typewriter
usart
\family default
.
\end_layout

\begin_layout Enumerate
Adjust 
\family typewriter
/path/to/sdcc/device/include/pic16/adc.h
\newline

\family default
Add the new devices to the correct ADC style class.
\end_layout

\end_deeper
\begin_layout Enumerate
Edit 
\family typewriter
/path/to/sdcc/device/include/pic16/pic18fregs.h
\family default
.
 The file format is self-explanatory, just add
\newline

\family typewriter
#elif defined(picDEVICE)
\newline
# include <picDEVICE.h>
\family default

\newline
at the right place (keep it sorted).
\end_layout

\begin_layout Enumerate
Edit 
\family typewriter
/path/to/sdcc/device/include/pic16devices.txt
\newline

\family default
Copy and modify an existing entry or create a new one and insert it at the
 correct place (keep the file sorted).
\end_layout

\begin_layout Enumerate
Recompile the pic16 libraries.
\end_layout

\begin_layout Subsection
Memory Models
\end_layout

\begin_layout Standard
The following memory models are supported by the PIC16 port:
\end_layout

\begin_layout Itemize
small model
\end_layout

\begin_layout Itemize
large model
\end_layout

\begin_layout Standard
Memory model affects the default size of pointers within the source.
 The sizes are shown in the next table:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="3" columns="3">
<features>
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Pointer sizes according to memory model
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
small model
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
large model
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
code pointers
\end_layout

\end_inset
</cell>
<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
16-bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
24-bits
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
data pointers
\end_layout

\end_inset
</cell>
<cell multicolumn="1" alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
16-bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
16-bits
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
It is advisable that all sources within a project are compiled with the
 same memory model.
 If one wants to override the default memory model, this can be done by
 declaring a pointer as 
\series bold
far
\series default
 or 
\series bold
near
\series default
.
 Far selects large memory model's pointers, while near selects small memory
 model's pointers.
\end_layout

\begin_layout Standard
The standard device libraries (see 
\begin_inset LatexCommand \ref{sub:PIC16_Header-Files}

\end_inset

) contain no reference to pointers, so they can be used with both memory
 models.
\end_layout

\begin_layout Subsection
Stack
\end_layout

\begin_layout Standard
The stack
\begin_inset LatexCommand \index{PIC16!stack}

\end_inset

 implementation for the PIC16 port uses two indirect registers, FSR1 and
 FSR2.
\end_layout

\begin_layout Description
FSR1 is assigned as stack pointer
\end_layout

\begin_layout Description
FSR2 is assigned as frame pointer
\end_layout

\begin_layout Standard
The following stack models are supported by the PIC16 port
\end_layout

\begin_layout Itemize

\noun on
small
\noun default
 model
\end_layout

\begin_layout Itemize

\noun on
large
\noun default
 model
\end_layout

\begin_layout Standard

\noun on
Small
\noun default
 model means that only the FSRxL byte is used to access stack and frame,
 while 
\emph on
\noun on
large
\emph default
\noun default
 uses both FSRxL and FSRxH registers.
 The following table shows the stack/frame pointers sizes according to stack
 model and the maximum space they can address:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="3" columns="3">
<features>
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Stack & Frame pointer sizes according to stack model
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
small
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
large
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Stack pointer FSR1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
8-bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
16-bits
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Frame pointer FSR2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
8-bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
16-bits
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard

\noun on
Large 
\noun default
stack model is currently not working properly throughout the code generator.
 So its use is not advised.
 Also there are some other points that need special care:
\newline

\end_layout

\begin_layout Enumerate
Do not create stack sections with size more than one physical bank (that
 is 256 bytes)
\end_layout

\begin_layout Enumerate
Stack sections should no cross physical bank limits (i.e.
 #pragma stack 0x50 0x100)
\end_layout

\begin_layout Standard
These limitations are caused by the fact that only FSRxL is modified when
 using SMALL stack model, so no more than 256 bytes of stack can be used.
 This problem will disappear after LARGE model is fully implemented.
\end_layout

\begin_layout Subsection
Functions
\end_layout

\begin_layout Standard
In addition to the standard SDCC function keywords, PIC16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port makes available two more:
\end_layout

\begin_layout Description
wparam
\begin_inset LatexCommand \index{PIC16!wparam}

\end_inset

 Use the WREG to pass one byte of the first function argument.
 This improves speed but you may not use this for functions with arguments
 that are called via function pointers, otherwise the first byte of the
 first parameter will get lost.
 Usage:
\end_layout

\begin_layout LyX-Code
void func_wparam(int a) wparam
\end_layout

\begin_layout LyX-Code
{
\end_layout

\begin_layout LyX-Code
    /* WREG hold the lower part of a */
\end_layout

\begin_layout LyX-Code
    /* the high part of a is stored in FSR2+2 (or +3 for large stack model)
 */
\end_layout

\begin_layout LyX-Code
...
\end_layout

\begin_layout LyX-Code
}
\end_layout

\begin_layout Description
shadowregs
\begin_inset LatexCommand \index{PIC16!shadowregs}

\end_inset

 When entering/exiting an ISR, it is possible to take advantage of the PIC18F
 hardware shadow registers which hold the values of WREG, STATUS and BSR
 registers.
 This can be done by adding the keyword 
\emph on
shadowregs
\emph default
 before the 
\emph on
interrupt
\emph default
 keyword in the function's header.
\end_layout

\begin_layout LyX-Code
void isr_shadow(void) shadowregs interrupt 1
\end_layout

\begin_layout LyX-Code
{
\end_layout

\begin_layout LyX-Code
...
\end_layout

\begin_layout LyX-Code
}
\end_layout

\begin_layout Standard

\emph on
shadowregs
\emph default
 instructs the code generator not to store/restore WREG, STATUS, BSR when
 entering/exiting the ISR.
\end_layout

\begin_layout Subsection
Function return values
\end_layout

\begin_layout Standard
Return values from functions are placed to the appropriate registers following
 a modified Microchip policy optimized for SDCC.
 The following table shows these registers:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="2">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
size
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
destination register
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
8 bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
WREG
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
16 bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PRODL:WREG
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
24 bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PRODH:PRODL:WREG
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
32 bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
FSR0L:PRODH:PRODL:WREG
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
>32 bits
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
on stack, FSR0 points to the beginning
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Subsection
Interrupts
\end_layout

\begin_layout Standard
An interrupt
\begin_inset LatexCommand \index{PIC16!interrupt}

\end_inset

 service routine (ISR) is declared using the 
\emph on
interrupt
\emph default
 keyword.
\end_layout

\begin_layout LyX-Code
void isr(void) interrupt 
\emph on
n
\end_layout

\begin_layout LyX-Code
{
\end_layout

\begin_layout LyX-Code
...
\end_layout

\begin_layout LyX-Code
}
\end_layout

\begin_layout Standard

\emph on
n
\emph default
 is the interrupt number, which for PIC18F devices can be:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\emph on
n
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Interrupt Vector
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Interrupt Vector Address
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
RESET vector
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x000000
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
HIGH priority interrupts
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x000008
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
LOW priority interrupts
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0x000018
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
When generating assembly code for ISR the code generator places a 
\noun on
goto 
\noun default
instruction at the 
\emph on
Interrupt Vector Address
\emph default
 which points at the genetated ISR.
 This single GOTO instruction is part of an automatically generated 
\emph on
interrupt entry point
\emph default
 function.
 The actuall ISR code is placed as normally would in the code space.
 Upon interrupt request, the GOTO instruction is executed which jumps to
 the ISR code.
 When declaring interrupt functions as _naked this GOTO instruction is 
\series bold
not
\series default
 generated.
 The whole interrupt functions is therefore placed at the Interrupt Vector
 Address of the specific interrupt.
 This is not a problem for the LOW priority interrupts, but it is a problem
 for the RESET and the HIGH priority interrupts because code may be written
 at the next interrupt's vector address and cause undeterminate program
 behaviour if that interrupt is raised.
\begin_inset Foot
status open

\begin_layout Standard
This is not a problem when
\end_layout

\begin_layout Enumerate
this is a HIGH interrupt ISR and LOW interrupts are 
\emph on
disabled
\emph default
 or not used.
\end_layout

\begin_layout Enumerate
when the ISR is small enough not to reach the next interrupt's vector address.
\end_layout

\end_inset


\end_layout

\begin_layout Standard

\emph on
n
\emph default
 may be omitted.
 This way a function is generated similar to an ISR, but it is not assigned
 to any interrupt.
\end_layout

\begin_layout Standard
When entering an interrupt, currently the PIC16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port automatically saves the following registers:
\end_layout

\begin_layout Itemize
WREG
\end_layout

\begin_layout Itemize
STATUS
\end_layout

\begin_layout Itemize
BSR
\end_layout

\begin_layout Itemize
PROD (PRODL and PRODH)
\end_layout

\begin_layout Itemize
FSR0 (FSR0L and FSR0H)
\end_layout

\begin_layout Standard
These registers are restored upon return from the interrupt routine.
\begin_inset Foot
status open

\begin_layout Standard
NOTE that when the _naked attribute is specified for an interrupt routine,
 then NO registers are stored or restored.
\end_layout

\end_inset


\end_layout

\begin_layout Subsection
Generic Pointers
\end_layout

\begin_layout Standard
Generic pointers are implemented in PIC16 port as 3-byte (24-bit) types.
 There are 3 types of generic pointers currently implemented data, code
 and eeprom pointers.
 They are differentiated by the value of the 7th and 6th bits of the upper
 byte:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="5" columns="5">
<features>
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="center" valignment="top" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="center" valignment="top" width="0">
<column alignment="left" valignment="top" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
pointer type
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
7th bit
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
6th bit
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
rest of the pointer
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
description
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
data 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
\shape slanted
\emph on
uuuuuu uuuuxxxx xxxxxxxx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
a 12-bit data pointer in data RAM memory
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
code
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
\shape slanted
\emph on
uxxxxx xxxxxxxx xxxxxxxx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
a 21-bit code pointer in FLASH memory
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
eeprom
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
\shape slanted
\emph on
uuuuuu uuuuuuxx xxxxxxxx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
a 10-bit eeprom pointer in EEPROM memory
\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
(unimplemented)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
\shape slanted
\emph on
xxxxxx xxxxxxxx xxxxxxxx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
unimplemented pointer type
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
Generic pointer are read and written with a set of library functions which
 read/write 1, 2, 3, 4 bytes.
\end_layout

\begin_layout Subsection
PIC16 C Libraries
\end_layout

\begin_layout Subsubsection
Standard I/O Streams
\end_layout

\begin_layout Standard
In the 
\emph on
stdio.h
\emph default
 the type FILE is defined as:
\end_layout

\begin_layout LyX-Code
typedef char * FILE;
\end_layout

\begin_layout Standard
This type is the stream type implemented I/O in the PIC18F devices.
 Also the standard input and output streams are declared in stdio.h:
\end_layout

\begin_layout LyX-Code
extern FILE * stdin;
\end_layout

\begin_layout LyX-Code
extern FILE * stdout;
\end_layout

\begin_layout Standard
The FILE type is actually a generic pointer which defines one more type
 of generic pointers, the 
\emph on
stream 
\emph default
pointer.
 This new type has the format:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="2" columns="7">
<features>
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="center" valignment="top" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="center" valignment="top" width="0">
<column alignment="left" valignment="top" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
pointer type
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
<7:6>
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
<5>
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
<4>
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
<3:0>
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
rest of the pointer
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
descrption
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
stream
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
00
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
nnnn
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
\shape slanted
\emph on
uuuuuuuu uuuuuuuu
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
upper byte high nubble is 0x2n, the rest are zeroes
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
Currently implemented there are 3 types of streams defined:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="4">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
stream type
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
value
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
module
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
description
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
STREAM_USART
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
0x200000UL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
USART
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Writes/Reads characters via the USART peripheral
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
STREAM_MSSP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
0x210000UL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
MSSP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Writes/Reads characters via the MSSP peripheral
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
STREAM_USER
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family typewriter
0x2f0000UL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
(none)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Writes/Reads characters via used defined functions
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
The stream identifiers are declared as macros in the stdio.h header.
\end_layout

\begin_layout Standard
In the libc library there exist the functions that are used to write to
 each of the above streams.
 These are
\end_layout

\begin_layout Description
_
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

_stream_usart_putchar writes a character at the USART stream
\end_layout

\begin_layout Description
_
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

_stream_mssp_putchar writes a character at the MSSP stream
\end_layout

\begin_layout Description
putchar dummy function.
 This writes a character to a user specified manner.
\end_layout

\begin_layout Standard
In order to increase performance 
\emph on
putchar 
\emph default
is declared in stdio.h as having its parameter in WREG (it has the wparam
 keyword).
 In stdio.h exists the macro PUTCHAR(arg) that defines the putchar function
 in a user-friendly way.
 
\emph on
arg
\emph default
 is the name of the variable that holds the character to print.
 An example follows:
\end_layout

\begin_layout LyX-Code
#include <pic18fregs.h>
\newline
#include <stdio.h>
\newline

\newline
PUTCHAR( c )
\end_layout

\begin_layout LyX-Code
{
\end_layout

\begin_layout LyX-Code
    PORTA = c;    /* dump character c to PORTA */
\end_layout

\begin_layout LyX-Code
} 
\newline

\newline
void main(void)
\end_layout

\begin_layout LyX-Code
{
\end_layout

\begin_layout LyX-Code
    stdout = STREAM_USER;    /* this is not necessary, since stdout points
\end_layout

\begin_layout LyX-Code
                              * by default to STREAM_USER */
\end_layout

\begin_layout LyX-Code
    printf (
\begin_inset Quotes sld
\end_inset

This is a printf test
\backslash
n
\begin_inset Quotes srd
\end_inset

);
\end_layout

\begin_layout LyX-Code
}
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout Subsubsection
Printing functions
\end_layout

\begin_layout Standard
PIC16 contains an implementation of the printf-family of functions.
 There exist the following functions:
\end_layout

\begin_layout LyX-Code
extern unsigned int sprintf(char *buf, char *fmt, ...);
\end_layout

\begin_layout LyX-Code
extern unsigned int vsprintf(char *buf, char *fmt, va_list ap);
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
extern unsigned int printf(char *fmt, ...);
\end_layout

\begin_layout LyX-Code
extern unsigned int vprintf(char *fmt, va_lista ap);
\end_layout

\begin_layout LyX-Code

\end_layout

\begin_layout LyX-Code
extern unsigned int fprintf(FILE *fp, char *fmt, ...);
\end_layout

\begin_layout LyX-Code
extern unsigned int vfprintf(FILE *fp, char *fmt, va_list ap);
\end_layout

\begin_layout Standard
For sprintf and vsprintf 
\emph on
buf 
\emph default
should normally be a data pointer where the resulting string will be placed.
 No range checking is done so the user should allocate the necessery buffer.
 For fprintf and vfprintf 
\emph on
fp
\emph default
 should be a stream pointer (i.e.
 stdout, STREAM_MSSP, etc...).
\end_layout

\begin_layout Subsubsection
Signals
\end_layout

\begin_layout Standard
The PIC18F family of microcontrollers supports a number of interrupt sources.
 A list of these interrupts is shown in the following table:
\end_layout

\begin_layout Standard
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="11" columns="4">
<features>
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
signal name
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
description
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
signal name
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
descritpion
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_RB
\end_layout

\end_inset
</cell>
<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PORTB change interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_EE
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
EEPROM/FLASH write complete interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_INT0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
INT0 external interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_BCOL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Bus collision interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_INT1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
INT1 external interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_LVD
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Low voltage detect interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_INT2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
INT2 external interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_PSP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Parallel slave port interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_CCP1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
CCP1 module interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_AD
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
AD convertion complete interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_CCP2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
CCP2 module interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_RC
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
USART receive interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_TMR0
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
TMR0 overflow interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_TX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
USART transmit interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_TMR1
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
TMR1 overflow interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_MSSP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SSP receive/transmit interrupt
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_TMR2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
TMR2 matches PR2 interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SIG_TMR3
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
TMR3 overflow interrupt
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
The prototypes for these names are defined in the header file 
\emph on
signal.h
\emph default
 .
\end_layout

\begin_layout Standard
In order to simplify signal handling, a number of macros is provided:
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
DEF_INTHIGH(name) begin the definition of the interrupt dispatch table for
 high priority interrupts.
 
\emph on
name
\emph default
 is the function name to use.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
DEF_INTLOW(name) begin the definition of the interrupt dispatch table fo
 low priority interrupt.
 
\emph on
name
\emph default
 is the function name to use.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
DEF_HANDLER(sig,handler) define a handler for signal 
\emph on
sig.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
END_DEF end the declaration of the dispatch table.
\end_layout

\begin_layout Standard
Additionally there are two more macros to simplify the declaration of the
 signal handler:
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000

\series medium
SIGHANDLER(handler) 
\series default
this declares the function prototype for the 
\emph on
handler
\emph default
 function.
\end_layout

\begin_layout List
\labelwidthstring 00.00.0000
SIGHANDLERNAKED(handler) same as SIGHANDLER() but declares a naked function.
\end_layout

\begin_layout Standard
An example of using the macros above is shown below:
\end_layout

\begin_layout LyX-Code
#include <pic18fregs.h>
\end_layout

\begin_layout LyX-Code
#include <signal.h>
\newline

\newline
DEF_INTHIGH(high_int)
\end_layout

\begin_layout LyX-Code
DEF_HANDLER(SIG_TMR0, _tmr0_handler)
\end_layout

\begin_layout LyX-Code
DEF_HANDLER(SIG_BCOL, _bcol_handler)
\end_layout

\begin_layout LyX-Code
END_DEF
\newline

\newline
SIGHANDLER(_tmr0_handler)
\end_layout

\begin_layout LyX-Code
{
\end_layout

\begin_layout LyX-Code
  /* action to be taken when timer 0 overflows */
\end_layout

\begin_layout LyX-Code
}
\newline

\newline
SIGHANDLERNAKED(_bcol_handler)
\end_layout

\begin_layout LyX-Code
{
\end_layout

\begin_layout LyX-Code
  _asm
\end_layout

\begin_layout LyX-Code
    /* action to be taken when bus collision occurs */
\end_layout

\begin_layout LyX-Code
    retfie
\end_layout

\begin_layout LyX-Code
 _endasm;
\end_layout

\begin_layout LyX-Code
}
\end_layout

\begin_layout Standard

\series bold
NOTES:
\series default
 Special care should be taken when using the above scheme:
\end_layout

\begin_layout Itemize
do not place a colon (;) at the end of the DEF_* and END_DEF macros.
\end_layout

\begin_layout Itemize
when declaring SIGHANDLERNAKED handler never forget to use 
\emph on
retfie
\emph default
 for proper returning.
\end_layout

\begin_layout Subsection
PIC16 Port -- Tips
\end_layout

\begin_layout Standard
Here you can find some general tips for compiling programs with SDCC/pic16.
\end_layout

\begin_layout Subsubsection
Stack size
\end_layout

\begin_layout Standard
The default stack
\begin_inset LatexCommand \index{PIC16!stack}

\end_inset

 size (that is 64 bytes) probably is enough for many programs.
 One must take care that when there are many levels of function nesting,
 or there is excessive usage of stack, its size should be extended.
 An example of such a case is the printf/sprintf family of functions.
 If you encounter problems like not being able to print integers, then you
 need to set the stack size around the maximum (256 for small stack model).
 The following diagram shows what happens when calling printf to print an
 integer:
\end_layout

\begin_layout LyX-Code
printf () --> ltoa () --> ultoa () --> divschar ()
\end_layout

\begin_layout Standard
It is should be understood that stack is easily consumed when calling complicate
d functions.
 Using command line arguments like -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-fommit-frame-pointer might reduce stack usage by not creating unnecessery
 stack frames.
 Other ways to reduce stack usage may exist.
\end_layout

\begin_layout Subsection
Known Bugs
\end_layout

\begin_layout Standard
The PIC16 Port currently does not pass SDCC's regression test
\begin_inset LatexCommand \index{Regression test (PIC16)}

\end_inset

 suite (see section 
\begin_inset LatexCommand \ref{sec:Quality-control}

\end_inset

) and thus the snapshot build regression tests for the PIC16 target are
 currently disabled for all hosts
\emph on
.
\end_layout

\begin_layout Chapter
Debugging
\end_layout

\begin_layout Standard
There are several approaches to debugging your code.
 This chapter is meant to show your options and to give detail on some of
 them:
\newline

\newline
When writing your code:
\end_layout

\begin_layout Itemize
write your code with debugging in mind (avoid duplicating code, put conceptually
 similar variables into structs, use structured code, have strategic points
 within your code where all variables are consistent, ...)
\end_layout

\begin_layout Itemize
run a syntax-checking tool like splint
\begin_inset LatexCommand \index{splint (syntax checking tool)}

\end_inset


\begin_inset LatexCommand \index{lint (syntax checking tool)}

\end_inset

 (see -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-more-pedantic 
\begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}

\end_inset

) over the code.
\end_layout

\begin_layout Itemize
for the high level code use a C-compiler (like f.e.
 GCC) to compile run and debug the code on your host.
 See (see -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-more-pedantic 
\begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}

\end_inset

) on how to handle syntax extensions like __xdata, __at(), ...
 
\end_layout

\begin_layout Itemize
use another C-compiler to compile code for your target.
 Always an option but not recommended:) And not very likely to help you.
 If you seriously consider walking this path you should at least occasionally
 check portability of your code.
 Most commercial compiler vendors will offer an evaluation version so you
 can test compile your code or snippets of your code.
\end_layout

\begin_layout Standard
Debugging on a simulator:
\end_layout

\begin_layout Itemize
there is a separate section about SDCDB (section 
\begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}

\end_inset

) below.
\end_layout

\begin_layout Itemize
or (8051 specific) use a freeware/commercial simulator which interfaces
 to the AOMF
\begin_inset LatexCommand \index{AOMF, AOMF51}

\end_inset

 file (see 
\begin_inset LatexCommand \ref{OMF file}

\end_inset

) optionally generated by SDCC.
\end_layout

\begin_layout Standard
Debugging On-target: 
\end_layout

\begin_layout Itemize
use a MCU port pin to serially output debug data to the RS232 port of your
 host.
 You'll probably want some level shifting device typically involving a MAX232
 or similar IC.
 If the hardware serial port of the MCU is not available search for 'Software
 UART' in your favourite search machine.
\end_layout

\begin_layout Itemize
use an on-target monitor.
 In this context a monitor is a small program which usually accepts commands
 via a serial line and allows to set program counter, to single step through
 a program and read/write memory locations.
 For the 8051 good examples of monitors are paulmon and cmon51 (see section
 
\begin_inset LatexCommand \ref{sec:Related-open-source-tools}

\end_inset

).
\end_layout

\begin_layout Itemize
toggle MCU port pins at strategic points within your code and use an oscilloscop
e.
 A 
\emph on
digital oscilloscope
\emph default

\begin_inset LatexCommand \index{Oscilloscope}

\end_inset

 with deep trace memory is really helpful especially if you have to debug
 a realtime application.
 If you need to monitor more pins than your oscilloscope provides you can
 sometimes get away with a small R-2R network.
 On a single channel oscilloscope you could f.e.
 monitor 2 push-pull driven pins by connecting one via a 10\InsetSpace ~
k
\begin_inset Formula $\Omega$
\end_inset

 resistor and the other one by a 5\InsetSpace ~
k
\begin_inset Formula $\Omega$
\end_inset

 resistor to the oscilloscope probe (check output drive capability of the
 pins you want to monitor).
 If you need to monitor many more pins a 
\emph on
logic analyzer
\emph default
 will be handy.
\end_layout

\begin_layout Itemize
use an ICE (
\emph on
i
\emph default
n 
\emph on
c
\emph default
ircuit 
\emph on
e
\emph default
mulator
\begin_inset LatexCommand \index{ICE (in circuit emulator)}

\end_inset

).
 Usually very expensive.
 And very nice to have too.
 And usually locks you (for years...) to the devices the ICE can emulate.
 
\end_layout

\begin_layout Itemize
use a remote debugger.
 In most 8-bit systems the symbol information is not available on the target,
 and a complete debugger is too bulky for the target system.
 Therefore usually a debugger on the host system connects to an on-target
 debugging stub which accepts only primitive commands.
 
\newline
Terms to enter into your favourite search engine could be 'remote debugging',
 'gdb stub' or 'inferior debugger'.
 (is there one?)
\end_layout

\begin_layout Itemize
use an on target hardware debugger.
 Some of the more modern MCUs include hardware support for setting break
 points and monitoring/changing variables by using dedicated hardware pins.
 This facility doesn't require additional code to run on the target and
 
\emph on
usually
\emph default
 doesn't affect runtime behaviour until a breakpoint is hit.
 For the mcs51 most hardware debuggers use the AOMF
\begin_inset LatexCommand \index{AOMF, AOMF51}

\end_inset

 file (see 
\begin_inset LatexCommand \ref{OMF file}

\end_inset

) as input file.
 
\end_layout

\begin_layout Standard
Last not least:
\end_layout

\begin_layout Itemize
if you are not familiar with any of the following terms you're likely to
 run into problems rather sooner than later: 
\emph on
volatile
\emph default
, 
\emph on
atomic
\emph default
, 
\emph on
memory map
\emph default
, 
\emph on
overlay
\emph default
.
 As an embedded programmer you 
\emph on
have
\emph default
 to know them so why not look them up 
\emph on
before
\emph default
 you have problems?)
\end_layout

\begin_layout Itemize
tell someone else about your problem (actually this is a surprisingly effective
 means to hunt down the bug even if the listener is not familiar with your
 environment).
 As 'failure to communicate' is probably one of the job-induced deformations
 of an embedded programmer this is highly encouraged.
\end_layout

\begin_layout Section
Debugging with SDCDB
\begin_inset LatexCommand \label{cha:Debugging-with-SDCDB}

\end_inset


\begin_inset LatexCommand \index{SDCDB (debugger)}

\end_inset

 
\end_layout

\begin_layout Standard
SDCC is distributed with a source level debugger
\begin_inset LatexCommand \index{Debugger}

\end_inset

.
 The debugger uses a command line interface, the command repertoire of the
 debugger has been kept as close to gdb
\begin_inset LatexCommand \index{gdb}

\end_inset

 (the GNU debugger) as possible.
 The configuration and build process is part of the standard compiler installati
on, which also builds and installs the debugger in the target directory
 specified during configuration.
 The debugger allows you debug BOTH at the C source and at the ASM source
 level.
\end_layout

\begin_layout Subsection
Compiling for Debugging
\end_layout

\begin_layout Standard
The -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug
\begin_inset LatexCommand \index{-\/-debug}

\end_inset

 option must be specified for all files for which debug information is to
 be generated.
 The compiler generates a .adb file for each of these files.
 The linker creates the .cdb
\begin_inset LatexCommand \index{<file>.cdb}

\end_inset

 file from the .adb
\begin_inset LatexCommand \index{<file>.adb}

\end_inset

 files and the address information.
 This .cdb is used by the debugger.
\end_layout

\begin_layout Subsection
How the Debugger Works
\end_layout

\begin_layout Standard
When the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-debug option is specified the compiler generates extra symbol information
 some of which are put into the assembler source and some are put into the
 .adb file.
 Then the linker creates the .cdb file from the individual .adb files with
 the address information for the symbols.
 The debugger reads the symbolic information generated by the compiler &
 the address information generated by the linker.
 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
 execution is controlled by the debugger.
 When a command is issued for the debugger, it translates it into appropriate
 commands for the simulator.
 (Currently SDCDM only connects to the simulator but 
\emph on
newcdb
\emph default
 at 
\begin_inset LatexCommand \url{http://ec2drv.sf.net/}

\end_inset

 is an effort to connect directly to the hardware.) 
\end_layout

\begin_layout Subsection
Starting the Debugger SDCDB
\end_layout

\begin_layout Standard
The debugger can be started using the following command line.
 (Assume the file you are debugging has the file name foo).
\newline

\newline

\family sans
\series bold
sdcdb foo
\newline

\family default
\series default

\newline
The debugger will look for the following files.
\end_layout

\begin_layout Itemize
foo.c - the source file.
\end_layout

\begin_layout Itemize
foo.cdb - the debugger symbol information file.
\end_layout

\begin_layout Itemize
foo.ihx - the Intel hex format
\begin_inset LatexCommand \index{Intel hex format}

\end_inset

 object file.
\end_layout

\begin_layout Subsection
SDCDB Command Line Options
\end_layout

\begin_layout Itemize
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-directory=<source file directory> this option can used to specify the directory
 search list.
 The debugger will look into the directory list specified for source, cdb
 & ihx files.
 The items in the directory list must be separated by ':', e.g.
 if the source files can be in the directories /home/src1 and /home/src2,
 the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-directory option should be -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-directory=/home/src1:/home/src2.
 Note there can be no spaces in the option.
 
\end_layout

\begin_layout Itemize
-cd <directory> - change to the <directory>.
\end_layout

\begin_layout Itemize
-fullname - used by GUI front ends.
\end_layout

\begin_layout Itemize
-cpu <cpu-type> - this argument is passed to the simulator please see the
 simulator docs for details.
\end_layout

\begin_layout Itemize
-X <Clock frequency > this options is passed to the simulator please see
 the simulator docs for details.
\end_layout

\begin_layout Itemize
-s <serial port file> passed to simulator see the simulator docs for details.
\end_layout

\begin_layout Itemize
-S <serial in,out> passed to simulator see the simulator docs for details.
\end_layout

\begin_layout Itemize
-k <port number> passed to simulator see the simulator docs for details.
\end_layout

\begin_layout Subsection
SDCDB Debugger Commands
\end_layout

\begin_layout Standard
As mentioned earlier the command interface for the debugger has been deliberatel
y kept as close the GNU debugger gdb, as possible.
 This will help the integration with existing graphical user interfaces
 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
 If you use a graphical user interface for the debugger you can skip this
 section.
\end_layout

\begin_layout Subsubsection*
break [line | file:line | function | file:function]
\end_layout

\begin_layout Standard
Set breakpoint at specified line or function:
\newline

\newline

\family sans
\series bold
sdcdb>break 100 
\newline
sdcdb>break foo.c:100
\newline
sdcdb>break funcfoo
\newline
sdcdb>break foo.c:funcfoo
\end_layout

\begin_layout Subsubsection*
clear [line | file:line | function | file:function ]
\end_layout

\begin_layout Standard
Clear breakpoint at specified line or function:
\newline

\newline

\family sans
\series bold
sdcdb>clear 100
\newline
sdcdb>clear foo.c:100
\newline
sdcdb>clear funcfoo
\newline
sdcdb>clear foo.c:funcfoo
\end_layout

\begin_layout Subsubsection*
continue
\end_layout

\begin_layout Standard
Continue program being debugged, after breakpoint.
\end_layout

\begin_layout Subsubsection*
finish
\end_layout

\begin_layout Standard
Execute till the end of the current function.
\end_layout

\begin_layout Subsubsection*
delete [n]
\end_layout

\begin_layout Standard
Delete breakpoint number 'n'.
 If used without any option clear ALL user defined break points.
\end_layout

\begin_layout Subsubsection*
info [break | stack | frame | registers ]
\end_layout

\begin_layout Itemize
info break - list all breakpoints
\end_layout

\begin_layout Itemize
info stack - show the function call stack.
\end_layout

\begin_layout Itemize
info frame - show information about the current execution frame.
\end_layout

\begin_layout Itemize
info registers - show content of all registers.
\end_layout

\begin_layout Subsubsection*
step
\end_layout

\begin_layout Standard
Step program until it reaches a different source line.
 Note: pressing <return> repeats the last command.
\end_layout

\begin_layout Subsubsection*
next
\end_layout

\begin_layout Standard
Step program, proceeding through subroutine calls.
\end_layout

\begin_layout Subsubsection*
run
\end_layout

\begin_layout Standard
Start debugged program.
\end_layout

\begin_layout Subsubsection*
ptype variable 
\end_layout

\begin_layout Standard
Print type information of the variable.
\end_layout

\begin_layout Subsubsection*
print variable
\end_layout

\begin_layout Standard
print value of variable.
\end_layout

\begin_layout Subsubsection*
file filename
\end_layout

\begin_layout Standard
load the given file name.
 Note this is an alternate method of loading file for debugging.
\end_layout

\begin_layout Subsubsection*
frame
\end_layout

\begin_layout Standard
print information about current frame.
\end_layout

\begin_layout Subsubsection*
set srcmode
\end_layout

\begin_layout Standard
Toggle between C source & assembly source.
\end_layout

\begin_layout Subsubsection*
! simulator command
\end_layout

\begin_layout Standard
Send the string following '!' to the simulator, the simulator response is
 displayed.
 Note the debugger does not interpret the command being sent to the simulator,
 so if a command like 'go' is sent the debugger can loose its execution
 context and may display incorrect values.
\end_layout

\begin_layout Subsubsection*
quit
\end_layout

\begin_layout Standard
"Watch me now.
 Iam going Down.
 My name is Bobby Brown"
\end_layout

\begin_layout Subsection
Interfacing SDCDB with DDD
\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
The screenshot was converted from png to eps with: 
\begin_inset Quotes sld
\end_inset

bmeps -c -e8f -p3 ddd_example.png >ddd_example.eps
\begin_inset Quotes srd
\end_inset

 which produces a pretty compact eps file which is free from compression
 artifacts.
\end_layout

\begin_layout Standard
The screenshot was included in sdccman.lyx cvs version 1.120 but later removed
 as this broke the build system on Sourceforge (pdf-file was broken.
 pdflatex does not accept eps files).
\end_layout

\end_inset


\end_layout

\begin_layout Standard
The 
\emph on
p
\emph default
ortable 
\emph on
n
\emph default
etwork 
\emph on
g
\emph default
raphics File 
\size footnotesize

\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/doc/figures/ddd_example.png}

\end_inset


\size default
 shows a screenshot of a debugging session with DDD
\begin_inset LatexCommand \index{DDD (debugger)}

\end_inset

 (Unix only) on a simulated 8032.
 The debugging session might not run as smoothly as the screenshot suggests.
 The debugger allows setting of breakpoints, displaying and changing variables,
 single stepping through C and assembler code.
 
\newline
The source was compiled with 
\family sans
\series bold

\newline

\newline
sdcc -
\family default
\series default

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\family sans
\series bold
-debug ddd_example.c
\family default
\series default
 
\family sans
\series bold

\newline

\family default
\series default

\newline
and DDD was invoked with 
\family sans
\series bold

\newline

\newline
ddd -debugger "sdcdb -cpu 8032 ddd_example"
\end_layout

\begin_layout Standard
\begin_inset Note Note
status open

\begin_layout Standard
Check that the double quotes or an apostroph within the command line survive
 the LyX tool chain.
 Previously the apostrophs got slanted in the PDF output so a cut and paste
 did not work.
\end_layout

\end_inset


\end_layout

\begin_layout Subsection
Interfacing SDCDB with XEmacs
\begin_inset LatexCommand \index{XEmacs}

\end_inset


\begin_inset LatexCommand \index{Emacs}

\end_inset


\end_layout

\begin_layout Standard
Two files (in emacs lisp) are provided for the interfacing with XEmacs,
 sdcdb.el and sdcdbsrc.el.
 These two files can be found in the $(prefix)/bin directory after the installat
ion is complete.
 These files need to be loaded into XEmacs for the interface to work.
 This can be done at XEmacs startup time by inserting the following into
 your '.xemacs' file (which can be found in your HOME directory): 
\newline

\newline

\family typewriter
(load-file sdcdbsrc.el) 
\family default

\newline

\newline
.xemacs is a lisp file so the () around the command is REQUIRED.
 The files can also be loaded dynamically while XEmacs is running, set the
 environment variable 'EMACSLOADPATH' to the installation bin directory
 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
 To start the interface enter the following command: 
\newline

\newline

\family sans
\series bold
ESC-x sdcdbsrc
\family default
\series default

\newline

\newline
You will prompted to enter the file name to be debugged.
 
\newline

\newline
The command line options that are passed to the simulator directly are
 bound to default values in the file sdcdbsrc.el.
 The variables are listed below, these values maybe changed as required.
\end_layout

\begin_layout Itemize
sdcdbsrc-cpu-type '51
\end_layout

\begin_layout Itemize
sdcdbsrc-frequency '11059200
\end_layout

\begin_layout Itemize
sdcdbsrc-serial nil
\end_layout

\begin_layout Standard
The following is a list of key mapping for the debugger interface.
\end_layout

\begin_layout Standard
\InsetSpace ~

\family typewriter

\newline
;;\InsetSpace ~
Current Listing :: 
\newline
;;key\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
binding\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
Comment 
\newline
;;---\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-------\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-------
\newline
;; 
\newline
;;\InsetSpace ~
n\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-next-fro
m-src\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB next command 
\newline
;;\InsetSpace ~
b\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-back-from-src\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB back command 
\newline
;;\InsetSpace ~
c\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-cont-f
rom-src\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB continue command
\newline
;;\InsetSpace ~
s\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-step-from-src\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB step command 
\newline
;;\InsetSpace ~
?\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-w
hatis-c-sexp\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB ptypecommand for data at 
\newline
;;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
buffer point 
\newline
;;\InsetSpace ~
x\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdbsrc-delete\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCD
B Delete all breakpoints if no arg 
\newline
;;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
given or delete arg (C-u arg x) 
\newline
;;\InsetSpace ~
m\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdbsrc
-frame\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB Display current frame if no arg, 
\newline
;;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
given or display frame arg
 
\newline
;;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
buffer point 
\newline
;;\InsetSpace ~
!\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdbsrc-goto-sdcdb\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
Goto the SDCDB output buffer 
\newline
;;\InsetSpace ~
p\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-prin
t-c-sexp\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB print command for data at 
\newline
;;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
buffer point 
\newline
;;\InsetSpace ~
g\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdbsrc-goto-sdcdb\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
Got
o the SDCDB output buffer 
\newline
;;\InsetSpace ~
t\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdbsrc-mode\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
Toggles Sdcdbsrc mode (turns it
 off) 
\newline
;; 
\newline
;;\InsetSpace ~
C-c\InsetSpace ~
C-f\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-finish-from-src\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
SDCDB finish command 
\newline
;; 
\newline
;;\InsetSpace ~
C-x\InsetSpace ~
SPC\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdb-brea
k\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
Set break for line with point 
\newline
;;\InsetSpace ~
ESC\InsetSpace ~
t\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdcdbsrc-mode\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
Toggle Sdcdbsrc mode 
\newline
;;\InsetSpace ~
ESC\InsetSpace ~
m\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sdc
dbsrc-srcmode\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
Toggle list mode 
\newline
;; 
\newline

\family default

\newpage

\end_layout

\begin_layout Chapter
TIPS
\end_layout

\begin_layout Standard
Here are a few guidelines that will help the compiler generate more efficient
 code, some of the tips are specific to this compiler others are generally
 good programming practice.
\end_layout

\begin_layout Itemize
Use the smallest data type to represent your data-value.
 If it is known in advance that the value is going to be less than 256 then
 use an 'unsigned char' instead of a 'short' or 'int'.
 Please note, that ANSI C requires both signed and unsigned chars to be
 promoted to 'signed int'
\begin_inset LatexCommand \index{promotion to signed int}

\end_inset


\begin_inset Marginal
status collapsed

\begin_layout Standard

\series bold
\InsetSpace ~
!
\end_layout

\end_inset

 before doing any operation.
 This promotion
\begin_inset LatexCommand \index{type promotion}

\end_inset


\begin_inset LatexCommand \label{type promotion}

\end_inset

 can be omitted, if the result is the same.
 The effect of the promotion rules together with the sign-extension is often
 surprising:
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
unsigned char uc = 0xfe;
\newline
if (uc * uc < 0) /* this is true! */
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
....
\newline
}
\end_layout

\begin_layout Standard

\family typewriter
uc * uc
\family default
 is evaluated as 
\family typewriter
(int) uc * (int) uc = (int) 0xfe * (int) 0xfe = (int) 0xfc04 = -1024
\family default
.
 
\newline
Another one:
\end_layout

\begin_layout Verse

\family typewriter
(unsigned char) -12 / (signed char) -3 = ...
\end_layout

\begin_layout Standard
No, the result is not 4:
\end_layout

\begin_layout Verse

\family typewriter
(int) (unsigned char) -12 / (int) (signed char) -3 =
\newline
(int) (unsigned char)
 0xf4 / (int) (signed char) 0xfd =
\newline
(int) 0x00f4 / (int) 0xfffd =
\newline
(int) 0x00f4
 / (int) 0xfffd =
\newline
(int) 244 / (int) -3 =
\newline
(int) -81 = (int) 0xffaf;
\end_layout

\begin_layout Standard
Don't complain, that gcc gives you a different result.
 gcc uses 32 bit ints, while SDCC uses 16 bit ints.
 Therefore the results are different.
\newline
From 
\begin_inset Quotes sld
\end_inset

comp.lang.c FAQ
\begin_inset Quotes srd
\end_inset

:
\end_layout

\begin_layout Quote

\emph on
If well-defined overflow characteristics are important and negative values
 are not, or if you want to steer clear of sign-extension problems when
 manipulating bits or bytes, use one of the corresponding unsigned types.
 (Beware when mixing signed and unsigned values in expressions, though.)
\newline
Although
 character types (especially unsigned char) can be used as "tiny" integers,
 doing so is sometimes more trouble than it's worth, due to unpredictable
 sign extension and increased code size.
\end_layout

\end_deeper
\begin_layout Itemize
Use unsigned when it is known in advance that the value is not going to
 be negative.
 This helps especially if you are doing division or multiplication, bit-shifting
 or are using an array index.
\end_layout

\begin_layout Itemize
NEVER jump into a LOOP.
\end_layout

\begin_layout Itemize
Declare the variables to be local
\begin_inset LatexCommand \index{local variables}

\end_inset

 whenever possible, especially loop control variables (induction).
\end_layout

\begin_layout Itemize
Have a look at the assembly listing to get a 
\begin_inset Quotes sld
\end_inset

feeling
\begin_inset Quotes srd
\end_inset

 for the code generation.
\end_layout

\begin_layout Section
Porting code from or to other compilers
\begin_inset LatexCommand \label{sec:Porting-code-to-other-compilers}

\end_inset


\end_layout

\begin_layout Itemize
check whether endianness of the compilers differs and adapt where needed.
\end_layout

\begin_layout Itemize
check the device specific header files
\begin_inset LatexCommand \index{Header files}

\end_inset


\begin_inset LatexCommand \index{Include files}

\end_inset

 for compiler specific syntax.
 Eventually include the file <compiler.h
\begin_inset LatexCommand \index{compiler.h (include file)}

\end_inset

> 
\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/compiler.h?view=markup}

\end_inset

 to allow using common header files.
 (see f.e.
 cc2510fx.h 
\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/cc2510fx.h?view=markup}

\end_inset

).
\end_layout

\begin_layout Itemize
check whether the startup code contains the correct initialization (watchdog,
 peripherals).
\end_layout

\begin_layout Itemize
check whether the sizes of short, int, long match.
\end_layout

\begin_layout Itemize
check if some 16 or 32 bit hardware registers require a specific addressing
 order (least significant or most significant byte first) and adapt if needed
 (
\emph on
first
\emph default
 and 
\emph on
last
\emph default
 relate to time and not to lower/upper memory location here, so this is
 
\emph on
not
\emph default
 the same as endianness).
\end_layout

\begin_layout Itemize
check whether the keyword 
\emph on
volatile
\emph default
 is used where needed.
 The compilers might differ in their optimization characteristics (as different
 versions of the same compiler might also use more clever optimizations
 this is good idea anyway).
 See section 
\begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}

\end_inset

.
\end_layout

\begin_layout Itemize
check that the compilers are not told to supress warnings.
\end_layout

\begin_layout Itemize
check and convert compiler specific extensions (interrupts, memory areas,
 pragmas etc.).
\end_layout

\begin_layout Itemize
check for differences in type promotion.
 Especially check for math operations on 
\family typewriter
char
\family default
 or 
\family typewriter
unsigned char
\family default
 variables.
 For the sake of C99 compatibility SDCC will probably promote these to 
\family typewriter
int
\family default
 more often than other compilers.
 Eventually insert explicit casts to 
\family typewriter
(char) 
\family default
or
\family typewriter
 (unsigned char)
\family default
.
 Also check that the ~\InsetSpace ~
operator
\begin_inset LatexCommand \index{\~\/ Operator}

\end_inset

 is not used on 
\family typewriter
bit
\begin_inset LatexCommand \index{bit}

\end_inset


\family default
 variables, use the !\InsetSpace ~
operator instead.
 See sections 
\begin_inset LatexCommand \ref{type promotion}

\end_inset

 and 
\begin_inset LatexCommand \ref{sec:Compatibility-with-previous}

\end_inset

.
\end_layout

\begin_layout Itemize
check the assembly code generated for interrupt routines (f.e.
 for calls to possibly non-reentrant library functions).
\end_layout

\begin_layout Itemize
check whether timing loops result in proper timing (or preferably consider
 a rewrite of the code with timer based delays instead).
\end_layout

\begin_layout Itemize
check for differences in printf parameters (some compilers push (va_arg
\begin_inset LatexCommand \index{vararg, va\_arg}

\end_inset

) char variables as 
\family typewriter
int
\family default
 others push them as 
\family typewriter
char
\family default
.
 See section 
\begin_inset LatexCommand \ref{sec:Compatibility-with-previous}

\end_inset

).
\end_layout

\begin_layout Itemize
check the resulting memory map
\begin_inset LatexCommand \index{Memory map}

\end_inset

.
 Usage of different memory spaces: code, stack, data (for mcs51/ds390 additional
ly idata, pdata, xdata).
 Eventually check if unexpected library functions are included.
\end_layout

\begin_layout Section
Tools
\begin_inset LatexCommand \index{Tools}

\end_inset

 included in the distribution
\end_layout

\begin_layout Standard
\align left
\begin_inset Tabular
<lyxtabular version="3" rows="12" columns="3">
<features>
<column alignment="left" valignment="top" leftline="true" width="0pt">
<column alignment="left" valignment="top" leftline="true" width="0pt">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Name
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Purpose
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Directory
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
uCsim
\begin_inset LatexCommand \index{uCsim}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Simulator for various architectures
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/sim/ucsim
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
keil2sdcc.pl
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
header file
\begin_inset LatexCommand \index{Header files}

\end_inset


\begin_inset LatexCommand \index{Include files}

\end_inset

 conversion
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/support/scripts
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
mh2h.c
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
header file conversion
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/support/scripts
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
as-gbz80
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Assembler
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
as-z80
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Assembler
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
asx8051
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Assembler
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCDB
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Simulator
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
aslink
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Linker
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
link-z80
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Linker
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
link-gbz80
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Linker
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
packihx
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Intel Hex packer 
\begin_inset LatexCommand \index{packihx (tool)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/bin
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Section
Documentation
\begin_inset LatexCommand \index{Documentation}

\end_inset

 included in the distribution
\end_layout

\begin_layout Standard
\align left
\begin_inset Tabular
<lyxtabular version="3" rows="10" columns="2">
<features>
<column alignment="block" valignment="top" leftline="true" width="40col%">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="60col%">
<row topline="true" bottomline="true" endhead="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Subject / Title
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Filename / Where to get
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC Compiler User Guide
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
You're reading it right now
\emph on
 \InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\emph default

\newline

\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/sdccman.pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Changelog of SDCC
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/Changelog
\emph on
 \InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\emph default

\newline

\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/ChangeLog}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
ASXXXX
\begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}

\end_inset


\begin_inset LatexCommand \index{Assembler documentation}

\end_inset

 Assemblers and
\newline
ASLINK
\begin_inset LatexCommand \index{aslink}

\end_inset


\begin_inset LatexCommand \index{Linker documentation}

\end_inset

 Relocating Linker
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/as/doc/asxhtm.html 
\emph on
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\emph default

\newline

\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC regression test
\begin_inset LatexCommand \index{Regression test}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/doc/test_suite_spec.pdf 
\emph on
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\emph default

\newline

\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/test_suite_spec.pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Various notes
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/doc/* 
\emph on
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\emph default

\newline

\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/doc/}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Notes on debugging with SDCDB
\begin_inset LatexCommand \index{SDCDB (debugger)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/debugger/README 
\emph on
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at
\emph default
:
\newline

\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/debugger/README}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
uCsim
\begin_inset LatexCommand \index{uCsim}

\end_inset

 Software simulator for microcontrollers
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
sdcc/sim/ucsim/doc
\family default
\series default
\shape default
\size default
\emph default
\bar default
\noun default
/index.html 
\emph on
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\emph default

\newline

\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/sim/ucsim/doc/index.html}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Temporary notes on the pic16
\begin_inset LatexCommand \index{PIC16}

\end_inset

 port
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/src/pic16/NOTES 
\emph on
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\newline

\emph default

\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/src/pic16/NOTES}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
SDCC internal documentation (debugging file format)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
sdcc/doc/
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
cdbfileformat.pd
\family default
\series default
\shape default
\size default
\emph default
\bar default
\noun default
f
\emph on
 \InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\hfill
online at:
\emph default

\newline

\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/cdbfileformat.pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Section
Related open source tools
\begin_inset LatexCommand \label{sec:Related-open-source-tools}

\end_inset


\begin_inset LatexCommand \index{Related tools}

\end_inset


\end_layout

\begin_layout Standard
\align left
\begin_inset Tabular
<lyxtabular version="3" rows="16" columns="3">
<features>
<column alignment="left" valignment="top" leftline="true" width="0pt">
<column alignment="block" valignment="top" leftline="true" width="30line%">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="40col%">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Name
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Purpose
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Where to get
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
gpsim
\begin_inset LatexCommand \index{gpsim (pic simulator)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PIC simulator
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
gputils
\begin_inset LatexCommand \index{gputils (pic tools)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
GNU PIC utilities
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
flP5
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
PIC programmer
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://freshmeat.net/projects/flp5/}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
ec2drv/newcdb
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Tools for Silicon Laboratories JTAG debug adapter, partly based on SDCDB
 (Unix only)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://sourceforge.net/projects/ec2drv}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
indent
\begin_inset LatexCommand \index{indent (source formatting tool)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Formats C source - Master of the white spaces
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://directory.fsf.org/GNU/indent.html}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
srecord
\begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Object file conversion, checksumming, ...
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://sourceforge.net/projects/srecord}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
objdump
\begin_inset LatexCommand \index{objdump (tool)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Object file conversion, ...
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Part of binutils (should be there anyway)
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
cmon51
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
8051 monitor (hex up-/download, single step, disassemble)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://sourceforge.net/projects/cmon51}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
doxygen
\begin_inset LatexCommand \index{doxygen (source documentation tool)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Source code documentation system
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.doxygen.org}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
kdevelop
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
IDE (has anyone tried integrating SDCC & SDCDB? Unix only)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.kdevelop.org}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
paulmon
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
8051 monitor (hex up-/download, single step, disassemble)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/paulmon2.html}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
splint
\begin_inset LatexCommand \index{splint (syntax checking tool)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Statically checks c sources (see 
\begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}

\end_inset

)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.splint.org}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
ddd
\begin_inset LatexCommand \index{DDD (debugger)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Debugger, serves nicely as GUI to SDCDB
\begin_inset LatexCommand \index{SDCDB (debugger)}

\end_inset

 (Unix only)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
d52
\begin_inset LatexCommand \index{d52}

\end_inset


\begin_inset LatexCommand \index{d52 (disassembler)}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Disassembler, can count instruction cycles
\begin_inset LatexCommand \index{instruction cycles (count)}

\end_inset

, use with options -pnd
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.8052.com/users/disasm/}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
cmake
\begin_inset LatexCommand \index{cmake}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Cross platform build system, generates Makefiles
\begin_inset LatexCommand \index{Makefile}

\end_inset

 and project workspaces
\begin_inset LatexCommand \index{project workspace}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.cmake.org}

\end_inset

 \InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
and a dedicated wiki entry: 
\begin_inset LatexCommand \url{http://www.cmake.org/Wiki/CmakeSdcc}

\end_inset


\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Section
Related documentation / recommended reading
\end_layout

\begin_layout Standard
\align left
\begin_inset Tabular
<lyxtabular version="3" rows="7" columns="3">
<features>
<column alignment="left" valignment="top" leftline="true" width="0pt">
<column alignment="left" valignment="top" leftline="true" width="0">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Name
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Subject / Title
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
Where to get
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
c-refcard.pdf
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
C Reference Card
\begin_inset LatexCommand \index{C Reference card}

\end_inset

, 2 pages
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://refcards.com/refcards/c/index.html}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
c-faq
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
C-FAQ
\begin_inset LatexCommand \index{C FAQ}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset LatexCommand \url{http://www.c-faq.com}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
ISO/IEC 9899:TC2
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset Quotes sld
\end_inset

C-Standard
\begin_inset Quotes srd
\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
ISO/IEC DTR 18037
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
\begin_inset Quotes sld
\end_inset

Extensions for Embedded C
\begin_inset Quotes srd
\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1021.pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Latest datasheet of target CPU
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
vendor
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
Revision history of datasheet
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard
vendor
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\newline

\end_layout

\begin_layout Section
Application notes specifically for SDCC
\end_layout

\begin_layout Standard
SDCC makes no claims about the completeness of this list and about up-to-datenes
s or correctness of the application notes
\begin_inset LatexCommand \index{Application notes}

\end_inset

.
\end_layout

\begin_layout Standard
\align left

\size footnotesize
\begin_inset Tabular
<lyxtabular version="3" rows="7" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="17col%">
<column alignment="block" valignment="top" leftline="true" width="27col%">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="57col%">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
\size footnotesize
Vendor
\end_layout

\end_inset
</cell>
<cell alignment="left" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
\size footnotesize
Subject / Title
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\series bold
\size footnotesize
Where to get
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Maxim / Dallas
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Using the SDCC Compiler for the DS80C400
\begin_inset LatexCommand \index{DS80C400}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3346.pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Maxim / Dallas
\end_layout

\end_inset
</cell>
<cell multicolumn="1" alignment="left" valignment="top" topline="true" leftline="true" usebox="none" width="30line%">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Using the Free SDCC C Compiler to Develop Firmware for the DS89C420/430/440/450
\begin_inset LatexCommand \index{DS89C4x0}

\end_inset

 Family of Microcontrollers
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3477.pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Silicon Laboratories / Cygnal
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Integrating SDCC 8051 Tools Into The Silicon Labs IDE
\begin_inset LatexCommand \index{IDE}

\end_inset


\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://www.silabs.com/public/documents/tpub_doc/anote/Microcontrollers/en/an198.pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Ramtron / Goal Semiconductor
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Interfacing SDCC to Syn and Textpad
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Ramtron / Goal Semiconductor
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Installing and Configuring SDCC and Crimson Editor 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}

\end_inset


\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Texas Instruments
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
MSC12xx Programming with SDCC
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
\begin_inset LatexCommand \url{http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=sbaa109&fileType=pdf}

\end_inset


\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Section
Some Questions
\end_layout

\begin_layout Standard
Some questions answered, some pointers given - it might be time to in turn
 ask 
\emph on
you
\emph default
 some questions: 
\end_layout

\begin_layout Itemize
can you solve your project with the selected microcontroller? Would you
 find out early or rather late that your target is too small/slow/whatever?
 Can you switch to a slightly better device if it doesn't fit?
\end_layout

\begin_layout Itemize
should you solve the problem with an 8 bit CPU? Or would a 16/32 bit CPU
 and/or another programming language be more adequate? Would an operating
 system on the target device help?
\end_layout

\begin_layout Itemize
if you solved the problem, will the marketing department be happy?
\end_layout

\begin_layout Itemize
if the marketing department is happy, will customers be happy?
\end_layout

\begin_layout Itemize
if you're the project manager, marketing department and maybe even the customer
 in one person, have you tried to see the project from the outside?
\end_layout

\begin_layout Itemize
is the project done if you think it is done? Or is just that other interface/pro
tocol/feature/configuration/option missing? How about website, manual(s),
 internationali(z|s)ation, packaging, labels, 2nd source for components,
 electromagnetic compatability/interference, documentation for production,
 production test software, update mechanism, patent issues?
\end_layout

\begin_layout Itemize
is your project adequately positioned in that magic triangle: fame, fortune,
 fun?
\end_layout

\begin_layout Standard
Maybe not all answers to these questions are known and some answers may
 even be 
\emph on
no
\emph default
, nevertheless knowing these questions may help you to avoid burnout
\begin_inset Foot
status open

\begin_layout Standard
burnout is bad for electronic devices, programmers and motorcycle tyres
\end_layout

\end_inset

.
 Chances are you didn't want to hear some of them...
\end_layout

\begin_layout Chapter
Support
\begin_inset LatexCommand \index{Support}

\end_inset


\end_layout

\begin_layout Standard
SDCC has grown to be a large project.
 The compiler alone (without the preprocessor, assembler and linker) is
 well over 150,000 lines of code (blank stripped).
 The open source nature of this project is a key to its continued growth
 and support.
 You gain the benefit and support of many active software developers and
 end users.
 Is SDCC perfect? No, that's why we need your help.
 The developers take pride in fixing reported bugs.
 You can help by reporting the bugs and helping other SDCC users.
 There are lots of ways to contribute, and we encourage you to take part
 in making SDCC a great software package.
 
\end_layout

\begin_layout Standard
The SDCC project is hosted on the SDCC sourceforge site at 
\begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}

\end_inset

.
 You'll find the complete set of mailing lists
\begin_inset LatexCommand \index{Mailing list(s)}

\end_inset

, forums, bug reporting system, patch submission
\begin_inset LatexCommand \index{Patch submission}

\end_inset

 system, download
\begin_inset LatexCommand \index{download}

\end_inset

 area and Subversion code repository
\begin_inset LatexCommand \index{Subversion code repository}

\end_inset

 there.
\end_layout

\begin_layout Section
Reporting Bugs
\begin_inset LatexCommand \index{Bug reporting}

\end_inset


\begin_inset LatexCommand \index{Reporting bugs}

\end_inset


\end_layout

\begin_layout Standard
The recommended way of reporting bugs is using the infrastructure of the
 sourceforge site.
 You can follow the status of bug reports there and have an overview about
 the known bugs.
\end_layout

\begin_layout Standard
Bug reports are automatically forwarded to the developer mailing list and
 will be fixed ASAP.
 When reporting a bug, it is very useful to include a small test program
 (the smaller the better) which reproduces the problem.
 If you can isolate the problem by looking at the generated assembly code,
 this can be very helpful.
 Compiling your program with the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpall
\begin_inset LatexCommand \index{-\/-dumpall}

\end_inset

 option can sometimes be useful in locating optimization problems.
 When reporting a bug please make sure you:
\end_layout

\begin_layout Enumerate
Attach the code you are compiling with SDCC.
 
\end_layout

\begin_layout Enumerate
Specify the exact command you use to run SDCC, or attach your Makefile.
 
\end_layout

\begin_layout Enumerate
Specify the SDCC version (type "
\family sans
\series bold
sdcc -v
\family default
\series default
"), your platform, and operating system.
 
\end_layout

\begin_layout Enumerate
Provide an exact copy of any error message or incorrect output.
 
\end_layout

\begin_layout Enumerate
Put something meaningful in the subject of your message.
\end_layout

\begin_layout Standard
Please attempt to include these 5 important parts, as applicable, in all
 requests for support or when reporting any problems or bugs with SDCC.
 Though this will make your message lengthy, it will greatly improve your
 chance that SDCC users and developers will be able to help you.
 Some SDCC developers are frustrated by bug reports without code provided
 that they can use to reproduce and ultimately fix the problem, so please
 be sure to provide sample code if you are reporting a bug! 
\end_layout

\begin_layout Standard
Please have a short check that you are using a recent version of SDCC and
 the bug is not yet known.
 This is the link for reporting bugs: 
\begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}

\end_inset

.
 With SDCC on average having more than 200 downloads
\begin_inset LatexCommand \index{download}

\end_inset

 on sourceforge per day
\begin_inset Foot
status open

\begin_layout Standard
220 daily downloads on average Jan-Sept 2006 and about 150 daily downloads
 between 2002 and 2005.
 This does not include other methods of distribution.
\end_layout

\end_inset

 there must be some users.
 So it's not exactly easy to find a new bug.
 If you find one we need it: 
\emph on
reporting bugs is good
\emph default
.
\end_layout

\begin_layout Section
Requesting Features
\begin_inset LatexCommand \label{sub:Requesting-Features}

\end_inset


\begin_inset LatexCommand \index{Feature request}

\end_inset


\begin_inset LatexCommand \index{Requesting features}

\end_inset


\end_layout

\begin_layout Standard
Like bug reports feature requests are forwarded to the developer mailing
 list.
 This is the link for requesting features: 
\begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}

\end_inset

.
\end_layout

\begin_layout Section
Submitting patches
\end_layout

\begin_layout Standard
Like bug reports contributed patches are forwarded to the developer mailing
 list.
 This is the link for submitting patches
\begin_inset LatexCommand \index{Patch submission}

\end_inset

: 
\begin_inset LatexCommand \url{http://sourceforge.net/tracker/?group_id=599&atid=300599}

\end_inset

.
\end_layout

\begin_layout Standard
You need to specify some parameters to the 
\family typewriter
diff
\family default
 command for the patches to be useful.
 If you modified more than one file a patch created f.e.
 with 
\family sans
\series bold

\begin_inset Quotes sld
\end_inset

diff -Naur unmodified_directory modified_directory >my_changes.patch
\begin_inset Quotes srd
\end_inset


\family default
\series default
 will be fine, otherwise 
\family sans
\series bold

\begin_inset Quotes sld
\end_inset

diff -u sourcefile.c.orig sourcefile.c >my_changes.patch
\begin_inset Quotes srd
\end_inset


\series default
 
\family default
will do.
\end_layout

\begin_layout Section
Getting Help
\end_layout

\begin_layout Standard
These links should take you directly to the 
\begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}

\end_inset


\begin_inset Foot
status open

\begin_layout Standard
Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
 automated messages (mid 2003)
\end_layout

\end_inset

 and the 
\begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}

\end_inset

, lists
\begin_inset LatexCommand \index{Mailing list(s)}

\end_inset

 and forums are archived and searchable so if you are lucky someone already
 had a similar problem.
 While mails to the lists themselves are delivered promptly their web front
 end on sourceforge sometimes shows a severe time lag (up to several weeks),
 if you're seriously using SDCC please consider subscribing to the lists.
\end_layout

\begin_layout Section
ChangeLog
\end_layout

\begin_layout Standard
You can follow the status of the Subversion version
\begin_inset LatexCommand \index{version}

\end_inset

 of SDCC by watching the Changelog
\begin_inset LatexCommand \index{Changelog}

\end_inset

 in the Subversion repository
\size footnotesize
 
\begin_inset LatexCommand \htmlurl{http://sdcc.svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/ChangeLog}

\end_inset

.
\end_layout

\begin_layout Section
Subversion Source Code Repository
\end_layout

\begin_layout Standard
The output of 
\family sans
\series bold
sdcc -
\family default

\begin_inset ERT
status open

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\family sans
-version
\family default
\series default
 or the filenames of the snapshot versions of SDCC include date and its
 Subversion
\begin_inset LatexCommand \index{Subversion code repository}

\end_inset

 number.
 Subversion allows to download the source of recent or previous versions
 
\begin_inset LatexCommand \url{http://sourceforge.net/svn/?group_id=599}

\end_inset

 (by number or by date).
 An on-line source code browser and detailled instructions are also available
 there.
 SDCC versions starting from 1999 up to now are available (currently the
 versions prior to the conversion from cvs
\begin_inset LatexCommand \index{cvs|see{Subversion}}

\end_inset

 to Subversion (April 2006) are either by accessible by Subversion or by
 cvs).
\end_layout

\begin_layout Section
Release policy
\begin_inset LatexCommand \index{Release policy}

\end_inset


\end_layout

\begin_layout Standard
Historically there often were long delays between official releases and
 the sourceforge download area tends to get not updated at all.
 Excuses in the past might have referred to problems with live range analysis,
 but as this was fixed a while ago, the current problem is that another
 excuse has to be found.
 Kidding aside, we have to get better there! On the other hand there are
 daily snapshots available at 
\begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}

\end_inset

, and you can always build the very last version (hopefully with many bugs
 fixed, and features added) from the source code available at 
\begin_inset LatexCommand \htmlurl[Source]{http://sdcc.sourceforge.net/snap.php#Source}

\end_inset

.
 The SDCC Wiki
\begin_inset LatexCommand \index{wiki}

\end_inset


\begin_inset LatexCommand \index{SDCC Wiki}

\end_inset

 at 
\begin_inset LatexCommand \url{http://sdcc.wiki.sourceforge.net/}

\end_inset

 also holds some information about past and future releases.
\end_layout

\begin_layout Section
Examples
\begin_inset LatexCommand \index{Examples}

\end_inset


\end_layout

\begin_layout Standard
You'll find some small examples in the directory 
\emph on
sdcc/device/examples/.
 
\emph default
More examples and libraries are available at
\emph on
 The SDCC Open Knowledge Resource 
\begin_inset LatexCommand \url{http://sdccokr.dl9sec.de/}

\end_inset

 
\emph default
web site or at 
\begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/}

\end_inset

.
\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
I did insert a reference to Paul's web site here although it seems rather
 dedicated to a specific 8032 board (I think it's okay because it f.e.
 shows LCD/Harddisc interface and has a free 8051 monitor.
 Independent 8032 board vendors face hard competition of heavily subsidized
 development boards anyway).
\end_layout

\begin_layout Standard
Maybe we should include some links to real world applications.
 Preferably pointer to pointers (one for each architecture) so this stays
 manageable here?
\end_layout

\end_inset


\end_layout

\begin_layout Section
Quality control
\begin_inset LatexCommand \label{sec:Quality-control}

\end_inset


\begin_inset LatexCommand \index{Quality control}

\end_inset


\end_layout

\begin_layout Standard
The compiler is passed through snaphot build compile and build checks.
 The so called 
\shape italic
regression tests
\shape default

\begin_inset LatexCommand \index{Regression test}

\end_inset

 check that SDCC itself compiles flawlessly on several host platforms (i386,
 Opteron, 64 bit Alpha, ppc64, Mac OS X on ppc and i386, Solaris on Sparc)
 and checks the quality of the code generated by SDCC by running the code
 for several target platforms through simulators.
 The regression test suite comprises more than 100 files which expand to
 more than 500 test cases which include more than 4500 tests.
 The results of these tests are published daily on SDCC's snapshot page
 (click on the red or green symbols on the right side of 
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}

\end_inset

).
\end_layout

\begin_layout Standard
There is a separate document 
\shape italic
test_suite.pdf 
\begin_inset LatexCommand \index{Test suite}

\end_inset


\shape default
 
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/test_suite_spec.pdf}

\end_inset

 about the regression test suite.
\end_layout

\begin_layout Standard
You'll find the test code in the directory 
\shape italic
sdcc/support/regression
\shape default
.
 You can run these tests manually by running 
\family sans
make
\family default
 in this directory (or f.e.
 
\family sans
\series bold

\begin_inset Quotes sld
\end_inset

make test-mcs51
\begin_inset Quotes srd
\end_inset


\family default
\series default
 if you don't want to run the complete tests).
 The test code might also be interesting if you want to look for examples
\begin_inset LatexCommand \index{Examples}

\end_inset

 checking corner cases of SDCC or if you plan to submit patches
\begin_inset LatexCommand \index{Patch submission}

\end_inset

.
\end_layout

\begin_layout Standard
The PIC14 port uses a different set of regression tests 
\begin_inset LatexCommand \index{Regression test (PIC14)}

\end_inset

, you'll find them in the directory 
\shape italic
sdcc/src/regression
\shape default
.
\end_layout

\begin_layout Section
Use of SDCC in Education
\end_layout

\begin_layout Standard
In short: 
\emph on
highly
\emph default
 encouraged
\begin_inset Foot
status open

\begin_layout Standard
the phrase "use in education" might evoke the association "
\emph on
only
\emph default
 fit for use in education".
 This connotation is not intended but nevertheless risked as the licensing
 of SDCC makes it difficult to offer educational discounts
\end_layout

\end_inset

.
 If your rationales are to:
\end_layout

\begin_layout Enumerate
give students a chance to understand the 
\emph on
complete
\emph default
 steps of code generation
\end_layout

\begin_layout Enumerate
have a curriculum that can be extended for years.
 Then you could use an fpga board as target and your curriculum will seamlessly
 extend from logic synthesis (
\begin_inset LatexCommand \url[http://www.opencores.org]{opencores.org}

\end_inset

, 
\begin_inset LatexCommand \url[Oregano]{http://www.oregano.at/ip/ip01.htm}

\end_inset

), over assembly programming, to C to FPGA compilers (
\begin_inset LatexCommand \url[FPGAC]{http://sf.net/projects/fpgac}

\end_inset

) and to C.
\end_layout

\begin_layout Enumerate
be able to insert excursions about skills like using a revision control
 system, submitting/applying patches, using a type-setting (as opposed to
 word-processing) engine LyX/LaTeX, using 
\begin_inset LatexCommand \url[SourceForge]{http://www.sf.net}

\end_inset

, following some 
\begin_inset LatexCommand \url[netiquette]{http://en.wikipedia.org/wiki/Netiquette}

\end_inset

, understanding BSD/LGPL/GPL/Proprietary licensing, growth models of Open
 Source Software, CPU simulation, compiler regression tests
\begin_inset LatexCommand \index{Regression test}

\end_inset

.
 
\newline
And if there should be a shortage of ideas then you can always point students
 to the ever-growing feature request list 
\begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}

\end_inset

.
\end_layout

\begin_layout Enumerate
not tie students to a specific host platform and instead allow them to use
 a host platform of 
\emph on
their
\emph default
 choice (among them Alpha, i386, i386_64, Mac OS X, Mips, Sparc, Windows
 and eventually 
\begin_inset LatexCommand \url[OLPC]{http://www.laptop.org}

\end_inset

)
\end_layout

\begin_layout Enumerate
not encourage students to use illegal copies of educational software
\end_layout

\begin_layout Enumerate
be immune to licensing/availability/price changes of the chosen tool chain
\end_layout

\begin_layout Enumerate
be able to change to a new target platform without having to adopt a new
 tool chain
\end_layout

\begin_layout Enumerate
have complete control over and insight into the tool chain
\end_layout

\begin_layout Enumerate
make your students aware about the pros and cons of open source software
 development
\end_layout

\begin_layout Enumerate
give back to the public as you are probably at least partially publically
 funded
\end_layout

\begin_layout Enumerate
give students a chance to publically prove their skills and to possibly
 see a world wide impact
\end_layout

\begin_layout Standard
then SDCC is probably among the first choices.
 Well, probably SDCC might be the only choice.
\newpage

\end_layout

\begin_layout Chapter
SDCC Technical Data
\end_layout

\begin_layout Section
Optimizations
\begin_inset LatexCommand \index{Optimizations}

\end_inset


\end_layout

\begin_layout Standard
SDCC performs a host of standard optimizations in addition to some MCU specific
 optimizations.
 
\end_layout

\begin_layout Subsection
Sub-expression Elimination
\begin_inset LatexCommand \index{Subexpression elimination}

\end_inset


\end_layout

\begin_layout Standard
The compiler does local and 
\emph on
g
\emph default
lobal 
\emph on
c
\emph default
ommon 
\emph on
s
\emph default
ubexpression 
\emph on
e
\emph default
limination, e.g.: 
\end_layout

\begin_layout Verse

\family typewriter
i = x + y + 1; 
\newline
j = x + y;
\end_layout

\begin_layout Standard
will be translated to
\end_layout

\begin_layout Verse

\family typewriter
iTemp = x + y; 
\newline
i = iTemp + 1; 
\newline
j = iTemp;
\end_layout

\begin_layout Standard
Some subexpressions are not as obvious as the above example, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
a->b[i].c = 10; 
\newline
a->b[i].d = 11;
\end_layout

\begin_layout Standard
In this case the address arithmetic a->b[i] will be computed only once;
 the equivalent code in C would be.
\end_layout

\begin_layout Verse

\family typewriter
iTemp = a->b[i]; 
\newline
iTemp.c = 10; 
\newline
iTemp.d = 11;
\end_layout

\begin_layout Standard
The compiler will try to keep these temporary variables in registers.
\end_layout

\begin_layout Subsection
Dead-Code Elimination
\begin_inset LatexCommand \index{Dead-code elimination}

\end_inset


\end_layout

\begin_layout Verse

\family typewriter
int global;
\newline

\newline
void f () { 
\newline
\InsetSpace ~
\InsetSpace ~
int i; 
\newline
\InsetSpace ~
\InsetSpace ~
i = 1; \InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* dead store */ 
\newline
\InsetSpace ~
\InsetSpace ~
global = 1;\InsetSpace ~
/* dead
 store */ 
\newline
\InsetSpace ~
\InsetSpace ~
global = 2; 
\newline
\InsetSpace ~
\InsetSpace ~
return; 
\newline
\InsetSpace ~
\InsetSpace ~
global = 3;\InsetSpace ~
/* unreachable */ 
\newline
}
\end_layout

\begin_layout Standard
will be changed to
\end_layout

\begin_layout Verse

\family typewriter
int global;
\newline

\newline
void f () {
\newline
\InsetSpace ~
\InsetSpace ~
global = 2; 
\newline
}
\end_layout

\begin_layout Subsection
Copy-Propagation
\begin_inset LatexCommand \index{Copy propagation}

\end_inset


\end_layout

\begin_layout Verse

\family typewriter
int f() { 
\newline
\InsetSpace ~
\InsetSpace ~
int i, j; 
\newline
\InsetSpace ~
\InsetSpace ~
i = 10; 
\newline
\InsetSpace ~
\InsetSpace ~
j = i; 
\newline
\InsetSpace ~
\InsetSpace ~
return j; 
\newline
}
\end_layout

\begin_layout Standard
will be changed to 
\end_layout

\begin_layout Verse

\family typewriter
int f() { 
\newline
\InsetSpace ~
\InsetSpace ~
int i, j; 
\newline
\InsetSpace ~
\InsetSpace ~
i = 10; 
\newline
\InsetSpace ~
\InsetSpace ~
j = 10; 
\newline
\InsetSpace ~
\InsetSpace ~
return 10; 
\newline
}
\end_layout

\begin_layout Standard
Note: the dead stores created by this copy propagation will be eliminated
 by dead-code elimination.
\end_layout

\begin_layout Subsection
Loop Optimizations
\begin_inset LatexCommand \index{Loop optimization}

\end_inset


\begin_inset LatexCommand \label{sub:Loop-Optimizations}

\end_inset


\end_layout

\begin_layout Standard
Two types of loop optimizations are done by SDCC 
\emph on
loop invariant
\emph default
 lifting and
\emph on
 strength reduction
\emph default
 of loop induction variables.
 In addition to the strength reduction the optimizer marks the induction
 variables and the register allocator tries to keep the induction variables
 in registers for the duration of the loop.
 Because of this preference of the register allocator
\begin_inset LatexCommand \index{Register allocation}

\end_inset

, loop induction optimization causes an increase in register pressure, which
 may cause unwanted spilling of other temporary variables into the stack
\begin_inset LatexCommand \index{stack}

\end_inset

 / data space.
 The compiler will generate a warning message when it is forced to allocate
 extra space either on the stack or data space.
 If this extra space allocation is undesirable then induction optimization
 can be eliminated either for the entire source file (with -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-noinduction option) or for a given function only using #pragma\InsetSpace ~
noinduction
\begin_inset LatexCommand \index{\#pragma noinduction}

\end_inset

.
\newline

\newline
Loop Invariant:
\end_layout

\begin_layout Verse

\family typewriter
for (i = 0 ; i < 100 ; i ++) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
f += k + l;
\end_layout

\begin_layout Standard
changed to
\end_layout

\begin_layout Verse

\family typewriter
itemp = k + l; 
\newline
for (i = 0; i < 100; i++) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
f += itemp;
\end_layout

\begin_layout Standard
As mentioned previously some loop invariants are not as apparent, all static
 address computations are also moved out of the loop.
\newline

\newline
Strength Reduction
\begin_inset LatexCommand \index{Strength reduction}

\end_inset

, this optimization substitutes an expression by a cheaper expression:
\end_layout

\begin_layout Verse

\family typewriter
for (i=0;i < 100; i++)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ar[i*5] = i*3;
\end_layout

\begin_layout Standard
changed to
\end_layout

\begin_layout Verse

\family typewriter
itemp1 = 0; 
\newline
itemp2 = 0; 
\newline
for (i=0;i< 100;i++) { 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
ar[itemp1] = itemp2; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
itemp1
 += 5; 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
itemp2 += 3; 
\newline
}
\end_layout

\begin_layout Standard
The more expensive multiplication
\begin_inset LatexCommand \index{Multiplication}

\end_inset

 is changed to a less expensive addition.
\end_layout

\begin_layout Subsection
Loop Reversing
\begin_inset LatexCommand \index{Loop reversing}

\end_inset


\end_layout

\begin_layout Standard
This optimization is done to reduce the overhead of checking loop boundaries
 for every iteration.
 Some simple loops can be reversed and implemented using a 
\begin_inset Quotes eld
\end_inset

decrement and jump if not zero
\begin_inset Quotes erd
\end_inset

 instruction.
 SDCC checks for the following criterion to determine if a loop is reversible
 (note: more sophisticated compilers use data-dependency analysis to make
 this determination, SDCC uses a more simple minded analysis).
\end_layout

\begin_layout Itemize
The 'for' loop is of the form 
\newline

\newline

\family typewriter
for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
 += 1])
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
<for body>
\end_layout

\begin_layout Itemize
The <for body> does not contain 
\begin_inset Quotes eld
\end_inset

continue
\begin_inset Quotes erd
\end_inset

 or 'break
\begin_inset Quotes erd
\end_inset

.
\end_layout

\begin_layout Itemize
All goto's are contained within the loop.
\end_layout

\begin_layout Itemize
No function calls within the loop.
\end_layout

\begin_layout Itemize
The loop control variable <sym> is not assigned any value within the loop
\end_layout

\begin_layout Itemize
The loop control variable does NOT participate in any arithmetic operation
 within the loop.
\end_layout

\begin_layout Itemize
There are NO switch statements in the loop.
\end_layout

\begin_layout Subsection
Algebraic Simplifications
\end_layout

\begin_layout Standard
SDCC does numerous algebraic simplifications, the following is a small sub-set
 of these optimizations.
\end_layout

\begin_layout Verse

\family typewriter
i = j + 0;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 /* changed to: */\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 i = j; 
\newline
i /= 2;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 /* changed to: */\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 i >>= 1; 
\newline
i
 = j - j;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 /* changed to: */\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 i = 0; 
\newline
i = j / 1;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 /* changed to: */\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 i = j;
\end_layout

\begin_layout Standard
Note the subexpressions
\begin_inset LatexCommand \index{Subexpression}

\end_inset

 given above are generally introduced by macro expansions or as a result
 of copy/constant propagation.
\end_layout

\begin_layout Subsection
'switch' Statements
\begin_inset LatexCommand \label{sub:'switch'-Statements}

\end_inset


\begin_inset LatexCommand \index{switch statement}

\end_inset


\end_layout

\begin_layout Standard
SDCC can optimize switch statements to jump tables
\begin_inset LatexCommand \index{jump tables}

\end_inset

.
 It makes the decision based on an estimate of the generated code size.
 SDCC is quite liberal in the requirements for jump table generation: 
\end_layout

\begin_layout Itemize
The labels need not be in order, and the starting number need not be one
 or zero, the case labels are in numerical sequence or not too many case
 labels are missing.
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
switch(i) {\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
switch (i) { 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 4: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 0: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 5: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 1: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 3: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 6: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 3: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 7: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 4: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 8: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 5: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 9: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 6: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 10: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 7: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 11: ...\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
case 8: ...
 
\newline
}\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
}
\end_layout

\begin_layout Standard
Both the above switch statements will be implemented using a jump-table.
 The example to the right side is slightly more efficient as the check for
 the lower boundary of the jump-table is not needed.
\end_layout

\end_deeper
\begin_layout Itemize
The number of case labels is not larger than supported by the target architectur
e.
\end_layout

\begin_layout Itemize
If the case labels are not in numerical sequence ('gaps' between cases)
 SDCC checks whether a jump table with additionally inserted dummy cases
 is still attractive.
 
\end_layout

\begin_layout Itemize
If the starting number is not zero and a check for the lower boundary of
 the jump-table can thus be eliminated SDCC might insert dummy cases 0,
 ...
 .
\end_layout

\begin_layout Standard
Switch statements which have large gaps in the numeric sequence or those
 that have too many case labels can be split into more than one switch statement
 for efficient code generation, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
switch (i) { 
\newline
\InsetSpace ~
\InsetSpace ~
case 1: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 2: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 3: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 4: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 5: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 6: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 7: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 101: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 102: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 103: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 104: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 105: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 106: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 107: ...
 
\newline
}
\end_layout

\begin_layout Standard
If the above switch statement is broken down into two switch statements
\end_layout

\begin_layout Verse

\family typewriter
switch (i) { 
\newline
\InsetSpace ~
\InsetSpace ~
case 1: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 2: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 3: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 4: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 5: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 6: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 7: ...
 
\newline
}
\end_layout

\begin_layout Standard
and
\end_layout

\begin_layout Verse

\family typewriter
switch (i) { 
\newline
\InsetSpace ~
\InsetSpace ~
case 101: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 102: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 103: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 104: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 105: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 106: ...
 
\newline
\InsetSpace ~
\InsetSpace ~
case 107: ...
 
\newline
}
\end_layout

\begin_layout Standard
then both the switch statements will be implemented using jump-tables whereas
 the unmodified switch statement will not be.
\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
There might be reasons which SDCC cannot know about to either favour or
 not favour jump tables.
 If the target system has to be as quick for the last switch case as for
 the first (pro jump table), or if the switch argument is known to be zero
 in the majority of the cases (contra jump table).
\end_layout

\end_inset


\end_layout

\begin_layout Standard
The pragma nojtbound
\begin_inset LatexCommand \index{\#pragma nojtbound}

\end_inset

 can be used to turn off checking the 
\emph on
j
\emph default
ump 
\emph on
t
\emph default
able 
\emph on
bound
\emph default
aries.
 It has no effect if a default label is supplied.
 Use of this pragma is dangerous: if the switch
\begin_inset LatexCommand \index{switch statement}

\end_inset

 argument is not matched by a case statement the processor will happily
 jump into Nirvana.
\end_layout

\begin_layout Subsection
Bit-shifting Operations
\begin_inset LatexCommand \index{Bit shifting}

\end_inset

.
\end_layout

\begin_layout Standard
Bit shifting is one of the most frequently used operation in embedded programmin
g.
 SDCC tries to implement bit-shift operations in the most efficient way
 possible, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
unsigned char i;
\newline
...
 
\newline
i >>= 4; 
\newline
...
\end_layout

\begin_layout Standard
generates the following code:
\end_layout

\begin_layout Verse

\family typewriter
mov\InsetSpace ~
 a,_i 
\newline
swap a 
\newline
anl\InsetSpace ~
 a,#0x0f 
\newline
mov\InsetSpace ~
 _i,a
\end_layout

\begin_layout Standard
In general SDCC will never setup a loop if the shift count is known.
 Another example:
\end_layout

\begin_layout Verse

\family typewriter
unsigned int i; 
\newline
...
 
\newline
i >>= 9; 
\newline
...
\end_layout

\begin_layout Standard
will generate:
\end_layout

\begin_layout Verse

\family typewriter
mov\InsetSpace ~
\InsetSpace ~
a,(_i + 1) 
\newline
mov\InsetSpace ~
\InsetSpace ~
(_i + 1),#0x00 
\newline
clr\InsetSpace ~
\InsetSpace ~
c 
\newline
rrc\InsetSpace ~
\InsetSpace ~
a 
\newline
mov\InsetSpace ~
\InsetSpace ~
_i,a
\end_layout

\begin_layout Subsection
Bit-rotation
\begin_inset LatexCommand \index{Bit rotation}

\end_inset


\end_layout

\begin_layout Standard
A special case of the bit-shift operation is bit rotation
\begin_inset LatexCommand \index{rotating bits}

\end_inset

, SDCC recognizes the following expression to be a left bit-rotation:
\end_layout

\begin_layout Verse

\family typewriter
\series bold
unsigned
\series default
\InsetSpace ~
\InsetSpace ~
char i;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* unsigned is needed for rotation */ 
\newline
...
 
\newline
i = ((i << 1) | (i >> 7)); 
\family default

\newline

\family typewriter
...
\end_layout

\begin_layout Standard
will generate the following code:
\end_layout

\begin_layout Verse

\family typewriter
mov\InsetSpace ~
\InsetSpace ~
a,_i 
\newline
rl\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
a 
\newline
mov\InsetSpace ~
\InsetSpace ~
_i,a
\end_layout

\begin_layout Standard
SDCC uses pattern matching on the parse tree to determine this operation.Variatio
ns of this case will also be recognized as bit-rotation, i.e.: 
\end_layout

\begin_layout Verse

\family typewriter
i = ((i >> 7) | (i << 1)); /* left-bit rotation */
\end_layout

\begin_layout Subsection
Nibble and Byte Swapping
\end_layout

\begin_layout Standard
Other special cases of the bit-shift operations are nibble or byte swapping
\begin_inset LatexCommand \index{swapping nibbles/bytes}

\end_inset

, SDCC recognizes the following expressions:
\end_layout

\begin_layout Verse

\family typewriter
\series bold
unsigned
\series default
\InsetSpace ~
\InsetSpace ~
char i; 
\newline

\series bold
unsigned
\series default
\InsetSpace ~
\InsetSpace ~
int j; 
\newline
...
 
\newline
i = ((i << 4) | (i >> 4)); 
\family default

\newline

\family typewriter
j = ((j << 8) | (j >> 8)); 
\end_layout

\begin_layout Standard
and generates a swap instruction for the nibble swapping
\begin_inset LatexCommand \index{Nibble swapping}

\end_inset

 or move instructions for the byte swapping
\begin_inset LatexCommand \index{Byte swapping}

\end_inset

.
 The 
\begin_inset Quotes sld
\end_inset

j
\begin_inset Quotes srd
\end_inset

 example can be used to convert from little to big-endian or vice versa.
 If you want to change the endianness of a 
\emph on
signed
\emph default
 integer you have to cast to 
\family typewriter
(unsigned int)
\family default
 first.
\end_layout

\begin_layout Standard
Note that SDCC stores numbers in little-endian
\begin_inset Foot
status open

\begin_layout Standard
Usually 8-bit processors don't care much about endianness.
 This is not the case for the standard 8051 which only has an instruction
 to increment its 
\emph on
dptr
\emph default

\begin_inset LatexCommand \index{DPTR}

\end_inset

-datapointer
\emph on
 
\emph default
so little-endian is the more efficient byte order.
\end_layout

\end_inset


\begin_inset LatexCommand \index{little-endian}

\end_inset


\begin_inset LatexCommand \index{Endianness}

\end_inset

 format (i.e.
 lowest order first).
\end_layout

\begin_layout Subsection
Highest Order Bit
\begin_inset LatexCommand \index{Highest Order Bit}

\end_inset

 / Any Order Bit
\begin_inset LatexCommand \index{Any Order Bit}

\end_inset


\end_layout

\begin_layout Standard
It is frequently required to obtain the highest order bit of an integral
 type (long, int, short or char types).
 Also obtaining any other order bit is not uncommon.
 SDCC recognizes the following expressions to yield the highest order bit
 and generates optimized code for it, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
unsigned int gint; 
\newline

\newline
foo () { 
\newline
\InsetSpace ~
\InsetSpace ~
unsigned char hob1, aob1; 
\newline
\InsetSpace ~
\InsetSpace ~
bit hob2, hob3, aob2,
 aob3; 
\newline
\InsetSpace ~
\InsetSpace ~
...
 
\newline
\InsetSpace ~
\InsetSpace ~
hob1 = (gint >> 15) & 1; 
\newline
\InsetSpace ~
\InsetSpace ~
hob2 = (gint >> 15) & 1; 
\newline
\InsetSpace ~
\InsetSpace ~
hob3 = gint & 0x8000;
 
\newline
\InsetSpace ~
\InsetSpace ~
aob1 = (gint >> 9) & 1; 
\newline
\InsetSpace ~
\InsetSpace ~
aob2 = (gint >> 8) & 1; 
\newline
\InsetSpace ~
\InsetSpace ~
aob3 = gint & 0x0800; 
\newline
\InsetSpace ~
\InsetSpace ~
..
 
\newline
}
\end_layout

\begin_layout Standard
will generate the following code:
\end_layout

\begin_layout Verse

\family typewriter
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 61 ;\InsetSpace ~
 hob.c 7 
\newline
000A E5*01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 62\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 a,(_gint + 1) 
\newline
000C 23\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 63\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 rl\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 a 
\newline
000D 54 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

 64\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 anl\InsetSpace ~
\InsetSpace ~
 a,#0x01 
\newline
000F F5*02\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 65\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_hob1_1_1,a 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 66 ;\InsetSpace ~
 hob.c 8 
\newline
0011 E5*01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

 67\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 a,(_gint + 1) 
\newline
0013 33\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 68\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 rlc\InsetSpace ~
\InsetSpace ~
 a 
\newline
0014 92*00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 69\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_hob2_1_1,c
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 66 ;\InsetSpace ~
 hob.c 9 
\newline
0016 E5*01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 67\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 a,(_gint + 1) 
\newline
0018 33\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 68\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 rlc\InsetSpace ~
\InsetSpace ~
 a 
\newline
0019 92*01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

 69\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_hob3_1_1,c 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 70 ;\InsetSpace ~
 hob.c 10 
\newline
001B E5*01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 71\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 a,(_gint + 1) 
\newline
001D
 03\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 72\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 rr\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 a 
\newline
001E 54 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 73\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 anl\InsetSpace ~
\InsetSpace ~
 a,#0x01 
\newline
0020 F5*03\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 74\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_aob1_1_1,a
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 75 ;\InsetSpace ~
 hob.c 11 
\newline
0022 E5*01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 76\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 a,(_gint + 1) 
\newline
0024 13\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 77\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 rrc\InsetSpace ~
\InsetSpace ~
 a 
\newline
0025 92*02\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

 78\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_aob2_1_1,c 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 79 ;\InsetSpace ~
 hob.c 12 
\newline
0027 E5*01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 80\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 a,(_gint + 1) 
\newline
0029
 A2 E3\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 81\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 c,acc[3] 
\newline
002B 92*03\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 82\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_aob3_1_1,c 
\end_layout

\begin_layout Standard
Other variations of these cases however will 
\emph on
not
\emph default
 be recognized.
 They are standard C expressions, so I heartily recommend these be the only
 way to get the highest order bit, (it is portable).
 Of course it will be recognized even if it is embedded in other expressions,
 e.g.:
\end_layout

\begin_layout Verse

\family typewriter
xyz = gint + ((gint >> 15) & 1);
\end_layout

\begin_layout Standard
will still be recognized.
\end_layout

\begin_layout Subsection
Higher Order Byte
\begin_inset LatexCommand \index{Higher Order Byte}

\end_inset

 / Higher Order Word
\begin_inset LatexCommand \index{Higher Order Word}

\end_inset


\end_layout

\begin_layout Standard
It is also frequently required to obtain a higher order byte or word of
 a larger integral type (long, int or short types).
 SDCC recognizes the following expressions to yield the higher order byte
 or word and generates optimized code for it, e.g.:
\end_layout

\begin_layout Verse

\family typewriter
unsigned int gint; 
\newline
unsigned long int glong; 
\newline

\newline
foo () { 
\newline
\InsetSpace ~
\InsetSpace ~
unsigned char hob1,
 hob2; 
\newline
\InsetSpace ~
\InsetSpace ~
unsigned int how1, how2; 
\newline
\InsetSpace ~
\InsetSpace ~
...
 
\newline
\InsetSpace ~
\InsetSpace ~
hob1 = (gint >> 8) & 0xFF; 
\newline
\InsetSpace ~
\InsetSpace ~
hob2 = glong >> 24; 
\newline
\InsetSpace ~
\InsetSpace ~
how1 = (glong >> 16) & 0xFFFF;
 
\newline
\InsetSpace ~
\InsetSpace ~
how2 = glong >> 8; 
\newline
\InsetSpace ~
\InsetSpace ~
..
 
\newline
}
\end_layout

\begin_layout Standard
will generate the following code:
\end_layout

\begin_layout Verse

\family typewriter
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 91 ;\InsetSpace ~
 hob.c 15 
\newline
0037 85*01*06\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 92\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_hob1_1_1,(_gint + 1) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 93 ;\InsetSpace ~
 hob.c
 16 
\newline
003A 85*05*07\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 94\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_hob2_1_1,(_glong + 3) 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 95 ;\InsetSpace ~
 hob.c 17 
\newline
003D 85*04*08\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

 96\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_how1_1_1,(_glong + 2) 
\newline
0040 85*05*09\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 97\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 (_foo_how1_1_1 +
 1),(_glong + 3) 
\newline
0043 85*03*0A\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 98\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 _foo_how2_1_1,(_glong + 1) 
\newline
0046 85*04*0B\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~

 99\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
 mov\InsetSpace ~
\InsetSpace ~
 (_foo_how2_1_1 + 1),(_glong + 2) 
\end_layout

\begin_layout Standard
Again, variations of these cases may 
\emph on
not
\emph default
 be recognized.
 They are standard C expressions, so I heartily recommend these be the only
 way to get the higher order byte/word, (it is portable).
 Of course it will be recognized even if it is embedded in other expressions,
 e.g.:
\end_layout

\begin_layout Verse

\family typewriter
xyz = gint + ((gint >> 8) & 0xFF);
\end_layout

\begin_layout Standard
will still be recognized.
\end_layout

\begin_layout Subsection
Peephole Optimizer
\begin_inset LatexCommand \label{sub:Peephole-Optimizer}

\end_inset


\begin_inset LatexCommand \index{Peephole optimizer}

\end_inset


\end_layout

\begin_layout Standard
The compiler uses a rule based, pattern matching and re-writing mechanism
 for peep-hole optimization.
 It is inspired by 
\emph on
copt
\emph default
 a peep-hole optimizer by Christopher W.
 Fraser (cwfraser\InsetSpace ~
@\InsetSpace ~
microsoft.com).
 A default set of rules are compiled into the compiler, additional rules
 may be added with the 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-peep-file
\begin_inset LatexCommand \index{-\/-peep-file}

\end_inset

 <filename>
\emph default
 option.
 The rule language is best illustrated with examples.
\end_layout

\begin_layout Verse

\family typewriter
replace { 
\newline
\InsetSpace ~
\InsetSpace ~
mov %1,a 
\newline
\InsetSpace ~
\InsetSpace ~
mov a,%1
\newline
} by {
\newline
\InsetSpace ~
\InsetSpace ~
mov %1,a
\newline
}
\end_layout

\begin_layout Standard
The above rule will change the following assembly
\begin_inset LatexCommand \index{Assembler routines}

\end_inset

 sequence:
\end_layout

\begin_layout Verse

\family typewriter
mov r1,a 
\newline
mov a,r1
\end_layout

\begin_layout Standard
to
\end_layout

\begin_layout Verse

\family typewriter
mov r1,a
\end_layout

\begin_layout Standard
Note: All occurrences of a 
\emph on
%n
\emph default
 (pattern variable) must denote the same string.
 With the above rule, the assembly sequence:
\end_layout

\begin_layout Verse

\family typewriter
mov r1,a 
\newline
mov a,r2
\end_layout

\begin_layout Standard
will remain unmodified.
\newline

\newline
Other special case optimizations may be added by the
 user (via 
\emph on
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-peep-file option
\emph default
).
 E.g.
 some variants of the 8051 MCU
\begin_inset LatexCommand \index{MCS51 variants}

\end_inset

 allow only 
\family typewriter
ajmp
\family default
 and 
\family typewriter
acall
\family default
.
 The following two rules will change all 
\family typewriter
ljmp
\family default
 and 
\family typewriter
lcall
\family default
 to 
\family typewriter
ajmp
\family default
 and 
\family typewriter
acall
\end_layout

\begin_layout Verse

\family typewriter
replace { lcall %1 } by { acall %1 } 
\newline
replace { ljmp %1 } by { ajmp %1 }
\end_layout

\begin_layout Standard
(NOTE: from version 2.7.3 on, you can use option -
\emph on

\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset


\emph default
-acall-ajmp
\begin_inset LatexCommand \index{-\/-acall-ajmp}

\end_inset

, which also takes care of aligning the interrupt vectors properly.)
\newline

\end_layout

\begin_layout Standard
The 
\emph on
inline-assembler code
\emph default
 is also passed through the peep hole optimizer, thus the peephole optimizer
 can also be used as an assembly level macro expander.
 The rules themselves are MCU dependent whereas the rule language infra-structur
e is MCU independent.
 Peephole optimization rules for other MCU can be easily programmed using
 the rule language.
\newline

\newline
The syntax for a rule is as follows:
\end_layout

\begin_layout Verse

\family typewriter
rule := replace [ restart ] '{' <assembly sequence> '
\backslash
n' 
\newline
\InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 '}' by '{' '
\backslash
n' 
\newline
\InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 <assembly sequence> '
\backslash
n' 
\newline
\InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
 '}' [if <functionName> ] '
\backslash
n' 
\end_layout

\begin_layout Standard
<assembly sequence> := assembly instruction (each instruction including
 labels must be on a separate line).
\newline

\newline
The optimizer will apply to the rules
 one by one from the top in the sequence of their appearance, it will terminate
 when all rules are exhausted.
 If the 'restart' option is specified, then the optimizer will start matching
 the rules again from the top, this option for a rule is expensive (performance)
, it is intended to be used in situations where a transformation will trigger
 the same rule again.
 An example of this (not a good one, it has side effects) is the following
 rule:
\end_layout

\begin_layout Verse

\family typewriter
replace restart { 
\newline
\InsetSpace ~
\InsetSpace ~
pop %1 
\newline
\InsetSpace ~
\InsetSpace ~
push %1 } by { 
\newline
\InsetSpace ~
\InsetSpace ~
; nop 
\newline
}
\end_layout

\begin_layout Standard
Note that the replace pattern cannot be a blank, but can be a comment line.
 Without the 'restart' option only the innermost 'pop' 'push' pair would
 be eliminated, i.e.:
\end_layout

\begin_layout Verse

\family typewriter
pop ar1 
\newline
pop ar2 
\newline
push ar2 
\newline
push ar1
\end_layout

\begin_layout Standard
would result in:
\end_layout

\begin_layout Verse

\family typewriter
pop ar1 
\newline
; nop 
\newline
push ar1
\end_layout

\begin_layout Standard

\emph on
with
\emph default
 the restart option the rule will be applied again to the resulting code
 and then all the pop-push pairs will be eliminated to yield:
\end_layout

\begin_layout Verse

\family typewriter
; nop 
\newline
; nop
\end_layout

\begin_layout Standard
A conditional function can be attached to a rule.
 Attaching rules are somewhat more involved, let me illustrate this with
 an example.
\end_layout

\begin_layout Verse

\family typewriter
replace { 
\newline
\InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
ljmp %5 
\newline
%2:
\newline
} by { 
\newline
\InsetSpace ~
 \InsetSpace ~
 \InsetSpace ~
sjmp %5 
\newline
%2:
\newline
} if labelInRange
\end_layout

\begin_layout Standard
The optimizer does a look-up of a function name table defined in function
 
\emph on
callFuncByName
\emph default
 in the source file SDCCpeeph.c, with the name 
\emph on
labelInRange
\emph default
.
 If it finds a corresponding entry the function is called.
 Note there can be no parameters specified for these functions, in this
 case the use of 
\emph on
%5
\emph default
 is crucial, since the function 
\emph on
labelInRange
\emph default
 expects to find the label in that particular variable (the hash table containin
g the variable bindings is passed as a parameter).
 If you want to code more such functions, take a close look at the function
 labelInRange and the calling mechanism in source file SDCCpeeph.c.
 Currently implemented are 
\emph on
labelInRange, labelRefCount, labelIsReturnOnly, operandsNotSame, xramMovcOption,
 24bitMode, portIsDS390, 24bitModeAndPortDS390 
\emph default
and
\emph on
 notVolatile
\emph default
.
\end_layout

\begin_layout Standard
I know this whole thing is a little kludgey, but maybe some day we will
 have some better means.
 If you are looking at this file, you will see the default rules that are
 compiled into the compiler, you can add your own rules in the default set
 there if you get tired of specifying the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-peep-file option.
\end_layout

\begin_layout Section
ANSI-Compliance
\begin_inset LatexCommand \index{ANSI-compliance}

\end_inset


\begin_inset LatexCommand \label{sub:ANSI-Compliance}

\end_inset


\end_layout

\begin_layout Standard
The latest publically available version of the standard 
\emph on
ISO/IEC 9899 - Programming languages - C
\emph default
 should be available at: 
\begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}

\end_inset

.
\newline

\end_layout

\begin_layout Standard
Deviations from the compliance:
\end_layout

\begin_layout Itemize
functions are not reentrant
\begin_inset LatexCommand \index{reentrant}

\end_inset

 unless explicitly declared as such or the 
\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-stack-auto
\begin_inset LatexCommand \index{-\/-stack-auto}

\end_inset


\series default
 command line option is specified.
\end_layout

\begin_layout Itemize
structures
\begin_inset LatexCommand \index{struct}

\end_inset

 and unions
\begin_inset LatexCommand \index{union}

\end_inset

 cannot be assigned values directly, cannot be passed as function parameters
 or assigned to each other and cannot be a return value
\begin_inset LatexCommand \index{return value}

\end_inset

 from a function, e.g.:
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
struct s { ...
 }; 
\newline
struct s s1, s2; 
\newline
foo() 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\newline

\series bold
struct
\series default
 s foo1 (
\series bold
struct
\series default
 s parms) /* invalid in SDCC although allowed in ANSI */
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
struct s rets;
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
return rets; /* is invalid in SDCC although allowed in ANSI */ 
\newline
}
\end_layout

\end_deeper
\begin_layout Itemize
initialization of structure arrays must be fully braced.
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
struct s { char x } a[] = {1, 2};\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* invalid in SDCC */
\newline
struct s { char x
 } a[] = {{1}, {2}}; /* OK */
\end_layout

\end_deeper
\begin_layout Itemize
'long long
\begin_inset LatexCommand \index{long long (not supported)}

\end_inset

' (64 bit integers
\begin_inset LatexCommand \index{int (64 bit) (not supported)}

\end_inset

) not supported.
\end_layout

\begin_layout Itemize
'double
\begin_inset LatexCommand \index{double (not supported)}

\end_inset

' precision floating point 
\begin_inset LatexCommand \index{Floating point support}

\end_inset

not supported.
\end_layout

\begin_layout Itemize
Old K&R style
\begin_inset LatexCommand \index{K\&R style}

\end_inset

 function declarations are NOT allowed.
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
foo(i,j) /* this old style of function declarations */ 
\newline
int i,j; /* is valid
 in ANSI but not valid in SDCC */ 
\newline
{ 
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
...
 
\newline
}
\end_layout

\end_deeper
\begin_layout Itemize
Most enhancements in C99 are not supported, e.g.:
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
for (
\series bold
int
\series default
 i=0; i<10; i++) /* is invalid in SDCC although allowed in C99 */
\end_layout

\end_deeper
\begin_layout Itemize
But some have been added recently in SDCC 2.7.0.
 They must be considered alpha quality however.
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
\series bold
inline
\begin_inset LatexCommand \index{inline (not supported)}

\end_inset


\series default
 int increment (int a) { return a+1; } /* inlines the increment without
 function call overhead */
\newline
int * 
\series bold
restrict
\begin_inset LatexCommand \index{inline (not supported)}

\end_inset


\series default
 p; /* accepted but ignored */
\end_layout

\end_deeper
\begin_layout Itemize
Certain words that are valid identifiers in the standard may be reserved
 words in SDCC unless the 
\series bold
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c89
\begin_inset LatexCommand \index{-\/-std-c89}

\end_inset

 
\series default
or
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c99
\begin_inset LatexCommand \index{-\/-std-c99}

\end_inset


\series default
 command line options are used.
 These may include (depending on the selected processor): 'at', 'banked',
 'bit', 'code', 'critical', 'data', 'eeprom', 'far', 'flash', 'idata', 'interrup
t', 'near', 'nonbanked', 'pdata', 'reentrant', 'sbit', 'sfr', 'shadowregs',
 'sram', 'using', 'wparam', 'xdata', '_overlay', '_asm', '_endasm', and
 '_naked'.
 Compliant equivalents of these keywords are always available in a form
 that begin with two underscores
\begin_inset LatexCommand \index{\_\_ (prefix for extended keywords)}

\end_inset

, f.e.
 '__data' instead of 'data'.
\end_layout

\begin_layout Itemize
Integer promotion of variable arguments is not performed if the argument
 is explicitly taypecasted unless the
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c89
\begin_inset LatexCommand \index{-\/-std-c89}

\end_inset

 
\series default
or
\series bold
 -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-std-c99
\begin_inset LatexCommand \index{-\/-std-c99}

\end_inset


\series default
 command line options are used.
\end_layout

\begin_deeper
\begin_layout Verse

\family typewriter
void vararg_func (char *str, ...) { str; }
\newline

\newline
void main (void)
\newline
{
\newline
\InsetSpace ~
\InsetSpace ~
char c = 10;
\newline

\newline
\InsetSpace ~
\InsetSpace ~
/* argument
 u is promoted to int before
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
* passing to function */
\newline
\InsetSpace ~
\InsetSpace ~
vararg_func ("%c", c);
\newline

\newline
\InsetSpace ~
\InsetSpace ~
/*
 argument u is not promoted to int,
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
* it is passed as char to function
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
* if
 --std-cXX is not defined;
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
* is promoted to int before passing
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
* to function
 if --std-cXX is defined */
\newline
\InsetSpace ~
\InsetSpace ~
vararg_func ("%bc", (char)u);
\newline
}
\end_layout

\end_deeper
\begin_layout Section
Cyclomatic Complexity
\begin_inset LatexCommand \index{Cyclomatic complexity}

\end_inset


\end_layout

\begin_layout Standard
Cyclomatic complexity of a function is defined as the number of independent
 paths the program can take during execution of the function.
 This is an important number since it defines the number test cases you
 have to generate to validate the function.
 The accepted industry standard for complexity number is 10, if the cyclomatic
 complexity reported by SDCC exceeds 10 you should think about simplification
 of the function logic.
 Note that the complexity level is not related to the number of lines of
 code in a function.
 Large functions can have low complexity, and small functions can have large
 complexity levels.
 
\newline

\newline
SDCC uses the following formula to compute the complexity:
\newline

\end_layout

\begin_layout Standard
complexity = (number of edges in control flow graph) - (number of nodes
 in control flow graph) + 2;
\newline

\newline
Having said that the industry standard is 10,
 you should be aware that in some cases it be may unavoidable to have a
 complexity level of less than 10.
 For example if you have switch statement with more than 10 case labels,
 each case label adds one to the complexity level.
 The complexity level is by no means an absolute measure of the algorithmic
 complexity of the function, it does however provide a good starting point
 for which functions you might look at for further optimization.
\end_layout

\begin_layout Section
Retargetting for other Processors
\end_layout

\begin_layout Standard
The issues for retargetting the compiler are far too numerous to be covered
 by this document.
 What follows is a brief description of each of the seven phases of the
 compiler and its MCU dependency.
\end_layout

\begin_layout Itemize
Parsing the source and building the annotated parse tree.
 This phase is largely MCU independent (except for the language extensions).
 Syntax & semantic checks are also done in this phase, along with some initial
 optimizations like back patching labels and the pattern matching optimizations
 like bit-rotation etc.
\end_layout

\begin_layout Itemize
The second phase involves generating an intermediate code which can be easy
 manipulated during the later phases.
 This phase is entirely MCU independent.
 The intermediate code generation assumes the target machine has unlimited
 number of registers, and designates them with the name iTemp.
 The compiler can be made to dump a human readable form of the code generated
 by using the -
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-dumpraw option.
\end_layout

\begin_layout Itemize
This phase does the bulk of the standard optimizations and is also MCU independe
nt.
 This phase can be broken down into several sub-phases:
\newline

\newline
Break down intermediate
 code (iCode) into basic blocks.
\newline
Do control flow & data flow analysis on the
 basic blocks.
\newline
Do local common subexpression elimination, then global subexpressio
n elimination
\newline
Dead code elimination
\newline
Loop optimizations
\newline
If loop optimizations
 caused any changes then do 'global subexpression elimination' and 'dead
 code elimination' again.
\end_layout

\begin_layout Itemize
This phase determines the live-ranges; by live range I mean those iTemp
 variables defined by the compiler that still survive after all the optimization
s.
 Live range analysis
\begin_inset LatexCommand \index{Live range analysis}

\end_inset

 is essential for register allocation, since these computation determines
 which of these iTemps will be assigned to registers, and for how long.
\end_layout

\begin_layout Itemize
Phase five is register allocation.
 There are two parts to this process.
\newline

\newline
The first part I call 'register packing'
 (for lack of a better term).
 In this case several MCU specific expression folding is done to reduce
 register pressure.
\newline

\newline
The second part is more MCU independent and deals with
 allocating registers to the remaining live ranges.
 A lot of MCU specific code does creep into this phase because of the limited
 number of index registers available in the 8051.
\end_layout

\begin_layout Itemize
The Code generation phase is (unhappily), entirely MCU dependent and very
 little (if any at all) of this code can be reused for other MCU.
 However the scheme for allocating a homogenized assembler operand for each
 iCode operand may be reused.
\end_layout

\begin_layout Itemize
As mentioned in the optimization section the peep-hole optimizer is rule
 based system, which can reprogrammed for other MCUs.
\end_layout

\begin_layout Standard
More information is available on SDCC Wiki
\begin_inset LatexCommand \index{wiki}

\end_inset

 (preliminary link 
\begin_inset LatexCommand \url{http://sdcc.wiki.sourceforge.net/SDCC+internals+and+porting}

\end_inset

) and in the thread 
\begin_inset LatexCommand \url{http://sf.net/mailarchive/message.php?msg_id=13954144}

\end_inset

 .
\end_layout

\begin_layout Chapter
Compiler internals
\begin_inset LatexCommand \index{Compiler internals}

\end_inset


\end_layout

\begin_layout Section
The anatomy of the compiler
\begin_inset LatexCommand \label{sub:The-anatomy-of}

\end_inset


\end_layout

\begin_layout Standard

\shape italic
This is an excerpt from an article published in Circuit Cellar Magazine
 in 
\series bold
August 2000
\series default
.
 It's a little outdated (the compiler is much more efficient now and user/develo
per friendly), but pretty well exposes the guts of it all.
\shape default

\newline

\newline
The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
 It is fairly easy to retarget for other 8-bit MCU.
 Here we take a look at some of the internals of the compiler.
 
\end_layout

\begin_layout Paragraph*
Parsing
\begin_inset LatexCommand \index{Parsing}

\end_inset

 
\end_layout

\begin_layout Standard
Parsing the input source file and creating an AST (Annotated Syntax Tree
\begin_inset LatexCommand \index{Annotated syntax tree}

\end_inset

).
 This phase also involves propagating types (annotating each node of the
 parse tree with type information) and semantic analysis.
 There are some MCU specific parsing rules.
 For example the storage classes, the extended storage classes are MCU specific
 while there may be a xdata storage class for 8051 there is no such storage
 class for z80 or Atmel AVR.
 SDCC allows MCU specific storage class extensions, i.e.
 xdata will be treated as a storage class specifier when parsing 8051 C
 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
 C code.
\end_layout

\begin_layout Paragraph*
Generating iCode
\begin_inset LatexCommand \index{iCode}

\end_inset


\end_layout

\begin_layout Standard
Intermediate code generation.
 In this phase the AST is broken down into three-operand form (iCode).
 These three operand forms are represented as doubly linked lists.
 ICode is the term given to the intermediate form generated by the compiler.
 ICode example section shows some examples of iCode generated for some simple
 C source functions.
\end_layout

\begin_layout Paragraph*
Optimizations
\begin_inset LatexCommand \index{Optimizations}

\end_inset

.
\end_layout

\begin_layout Standard
Bulk of the target independent optimizations is performed in this phase.
 The optimizations include constant propagation, common sub-expression eliminati
on, loop invariant code movement, strength reduction of loop induction variables
 and dead-code elimination.
\end_layout

\begin_layout Paragraph*
Live range analysis
\begin_inset LatexCommand \index{Live range analysis}

\end_inset


\end_layout

\begin_layout Standard
During intermediate code generation phase, the compiler assumes the target
 machine has infinite number of registers and generates a lot of temporary
 variables.
 The live range computation determines the lifetime of each of these compiler-ge
nerated temporaries.
 A picture speaks a thousand words.
 ICode example sections show the live range annotations for each of the
 operand.
 It is important to note here, each iCode is assigned a number in the order
 of its execution in the function.
 The live ranges are computed in terms of these numbers.
 The from number is the number of the iCode which first defines the operand
 and the to number signifies the iCode which uses this operand last.
\end_layout

\begin_layout Paragraph*
Register Allocation
\begin_inset LatexCommand \index{Register allocation}

\end_inset


\end_layout

\begin_layout Standard
The register allocation determines the type and number of registers needed
 by each operand.
 In most MCUs only a few registers can be used for indirect addressing.
 In case of 8051 for example the registers R0 & R1 can be used to indirectly
 address the internal ram and DPTR to indirectly address the external ram.
 The compiler will try to allocate the appropriate register to pointer variables
 if it can.
 ICode example section shows the operands annotated with the registers assigned
 to them.
 The compiler will try to keep operands in registers as much as possible;
 there are several schemes the compiler uses to do achieve this.
 When the compiler runs out of registers the compiler will check to see
 if there are any live operands which is not used or defined in the current
 basic block being processed, if there are any found then it will push that
 operand and use the registers in this block, the operand will then be popped
 at the end of the basic block.
 
\end_layout

\begin_layout Standard
There are other MCU specific considerations in this phase.
 Some MCUs have an accumulator; very short-lived operands could be assigned
 to the accumulator instead of a general-purpose register.
\end_layout

\begin_layout Paragraph*
Code generation
\end_layout

\begin_layout Standard
Figure II gives a table of iCode
\begin_inset LatexCommand \index{iCode}

\end_inset

 operations supported by the compiler.
 The code generation involves translating these operations into corresponding
 assembly code for the processor.
 This sounds overly simple but that is the essence of code generation.
 Some of the iCode operations are generated on a MCU specific manner for
 example, the z80 port does not use registers to pass parameters so the
 SEND and RECV iCode operations will not be generated, and it also does
 not support JUMPTABLES.
 
\newline

\end_layout

\begin_layout Standard

\size footnotesize
Figure II 
\begin_inset Tabular
<lyxtabular version="3" rows="39" columns="4">
<features islongtable="true" headBottomDL="true">
<column alignment="block" valignment="top" leftline="true" width="13col%">
<column alignment="left" valignment="top" leftline="true" width="13col%">
<column alignment="block" valignment="top" leftline="true" width="22col%">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="40col%">
<row topline="true" bottomline="true" endhead="true">
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iCode
\series default

\begin_inset LatexCommand \index{iCode}

\end_inset


\end_layout

\end_inset
</cell>
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\begin_inset Text

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\series bold
Operands
\end_layout

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\begin_inset Text

\begin_layout Standard

\series bold
Description
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

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\series bold
C Equivalent
\end_layout

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<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'!'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
NOT operation 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = ! IC_LEFT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'~'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Bitwise complement of 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = ~IC_LEFT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
RRC
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Rotate right with carry
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = (IC_LEFT << 1) | (IC_LEFT >> (sizeof(IC_LEFT)*8-1));
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
RLC
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Rotate left with carry
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = (IC_LEFT << (sizeof(LC_LEFT)*8-1) ) | (IC_LEFT >> 1);
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
GETHBIT
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Get the highest order bit of IC_LEFT
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = (IC_LEFT >> (sizeof(IC_LEFT)*8 -1));
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
UNARYMINUS
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Unary minus
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = - IC_LEFT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IPUSH
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Push the operand into stack
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
NONE
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IPOP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Pop the operand from the stack 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
NONE
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
CALL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Call the function represented by IC_LEFT 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT();
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
PCALL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Call via function pointer
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = (*IC_LEFT)();
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
RETURN
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Return the value in operand IC_LEFT 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
return IC_LEFT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
LABEL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LABEL() 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Label
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LABEL:
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
GOTO
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LABEL() 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Goto label
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
goto IC_LABEL();
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'+'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Addition
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT + IC_RIGHT
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'-'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Subtraction
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT - IC_RIGHT 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'*'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Multiplication 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT * IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'/'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Division
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT / IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'%'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Modulus
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT % IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'<'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Less than
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT < IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'>'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Greater than 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT > IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
EQ_OP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Equal to 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT == IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
AND_OP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT() 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Logical and operation
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT && IC_RIGHT; 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
OR_OP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT() 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Logical or operation 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT || IC_RIGHT; 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'^'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT() 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Exclusive OR
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT ^ IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'|'
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT() 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Bitwise OR 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT | IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
BITWISEAND
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Bitwise AND 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT & IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
LEFT_OP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Left shift 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT << IC_RIGHT 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
RIGHT_OP
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Right shift
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_LEFT >> IC_RIGHT 
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
GET_VALUE_
\newline
AT_ ADDRESS
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Indirect fetch 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = (*IC_LEFT);
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
POINTER_SET
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RIGHT() IC_RESULT() 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Indirect set
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
(*IC_RESULT) = IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
'='
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RIGHT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Assignment
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IFX
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_COND IC_TRUE IC_LABEL
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Conditional jump.
 If true label is present then jump to true label if condition is true else
 jump to false label if condition is false 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
if (IC_COND) goto IC_TRUE; 
\newline
\InsetSpace ~
\InsetSpace ~
Or 
\newline
If (!IC_COND) goto IC_FALSE;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
ADDRESS_OF
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Address of 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = &IC_LEFT();
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
JUMPTABLE
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_JTCOND IC_JTLABELS
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Jump to list of labels depending on the value of JTCOND
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Switch statement
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
CAST
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RIGHT() IC_LEFT() IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
Cast types 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT = (typeof IC_LEFT) IC_RIGHT;
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
SEND
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_LEFT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
This is used for passing parameters in registers; 
\newline
move IC_LEFT to the next
 available parameter register.
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
None
\end_layout

\end_inset
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
RECV
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
IC_RESULT()
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
This is used for receiving parameters passed in registers;
\newline
Move the values
 in the next parameter register to IC_RESULT 
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\size footnotesize
None
\end_layout

\end_inset
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\shape slanted
\size footnotesize
(some more have been added)
\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\end_layout

\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\begin_layout Standard

\shape slanted
\size footnotesize
see f.e.
 
\family typewriter
gen51Code()
\family default
 in 
\family typewriter
src/mcs51/gen.c
\end_layout

\end_inset
</cell>
</row>
</lyxtabular>

\end_inset


\end_layout

\begin_layout Standard
\begin_inset Note Note
status collapsed

\begin_layout Standard
In the original article Figure II was announced to be downloadable on 
\shape italic
Circuit Cellar
\shape default
's web site.
 ftp://ftp.circuitcellar.com/pub/Circuit_Cellar/2000/121/dutta.ZIP
\end_layout

\end_inset


\end_layout

\begin_layout Paragraph*
ICode Example
\begin_inset LatexCommand \index{iCode}

\end_inset


\end_layout

\begin_layout Standard
This section shows some details of iCode.
 The example C code does not do anything useful; it is used as an example
 to illustrate the intermediate code generated by the compiler.
\end_layout

\begin_layout Verse

\family typewriter
1.\InsetSpace ~
xdata int * p;
\newline
2.\InsetSpace ~
int gint;
\newline
3.\InsetSpace ~
/* This function does nothing useful.
 It is used
\newline
4.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
for the purpose of explaining iCode */
\newline
5.\InsetSpace ~
short function (data
 int *x)
\newline
6.\InsetSpace ~
{
\newline
7.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
short i=10; \InsetSpace ~
\InsetSpace ~
/* dead initialization eliminated */
\newline
8.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
short sum=10;
 /* dead initialization eliminated */
\newline
9.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
short mul;
\newline
10.\InsetSpace ~
\InsetSpace ~
int j ;
\newline
11.\InsetSpace ~
\InsetSpace ~
while (*x) *x++
 = *p++; 
\newline
12.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sum = 0 ; 
\newline
13.\InsetSpace ~
\InsetSpace ~
mul = 0;
\newline
14.\InsetSpace ~
\InsetSpace ~
/* compiler detects i,j to be induction
 variables */
\newline
15.\InsetSpace ~
\InsetSpace ~
for (i = 0, j = 10 ; i < 10 ; i++, j
\family default
-
\begin_inset ERT
status collapsed

\begin_layout Standard


\backslash
/
\end_layout

\end_inset

-
\family typewriter
) {
\newline
16.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
sum += i;
\newline
17.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
mul += i * 3; \InsetSpace ~
\InsetSpace ~
/* this multiplication remains */
\newline
18.\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
gint +=
 j * 3;\InsetSpace ~
\InsetSpace ~
/* this multiplication changed to addition */
\newline
19.\InsetSpace ~
\InsetSpace ~
}
\newline
20.\InsetSpace ~
\InsetSpace ~
return sum+mul;
\newline
21.\InsetSpace ~
}
\end_layout

\begin_layout Standard
In addition to the operands each iCode contains information about the filename
 and line it corresponds to in the source file.
 The first field in the listing should be interpreted as follows:
\newline

\shape italic
\size footnotesize
Filename(linenumber: iCode Execution sequence number : ICode hash table
 key : loop depth of the iCode).
\shape default
\size default

\newline
Then follows the human readable form of the ICode operation.
 Each operand of this triplet form can be of three basic types a) compiler
 generated temporary b) user defined variable c) a constant value.
 Note that local variables and parameters are replaced by compiler generated
 temporaries.
 Live ranges
\begin_inset LatexCommand \index{Live range analysis}

\end_inset

 are computed only for temporaries (i.e.
 live ranges are not computed for global variables).
 Registers
\begin_inset LatexCommand \index{Register allocation}

\end_inset

 are allocated for temporaries only.
 Operands are formatted in the following manner:
\newline

\shape italic
\size footnotesize
Operand Name [lr live-from : live-to ] { type information } [ registers
 allocated ].
\shape default
\size default

\newline
As mentioned earlier the live ranges are computed in terms of the execution
 sequence number of the iCodes, for example 
\newline
the iTemp0 is live from (i.e.
 first defined in iCode with execution sequence number 3, and is last used
 in the iCode with sequence number 5).
 For induction variables such as iTemp21 the live range computation extends
 the lifetime from the start to the end of the loop.
\newline
The register allocator
 used the live range information to allocate registers, the same registers
 may be used for different temporaries if their live ranges do not overlap,
 for example r0 is allocated to both iTemp6 and to iTemp17 since their live
 ranges do not overlap.
 In addition the allocator also takes into consideration the type and usage
 of a temporary, for example itemp6 is a pointer to near space and is used
 as to fetch data from (i.e.
 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer register (r0).
 Some short lived temporaries are allocated to special registers which have
 meaning to the code generator e.g.
 iTemp13 is allocated to a pseudo register CC which tells the back end that
 the temporary is used only for a conditional jump the code generation makes
 use of this information to optimize a compare and jump ICode.
\newline
There are several
 loop optimizations
\begin_inset LatexCommand \index{Loop optimization}

\end_inset

 performed by the compiler.
 It can detect induction variables iTemp21(i) and iTemp23(j).
 Also note the compiler does selective strength reduction
\begin_inset LatexCommand \index{Strength reduction}

\end_inset

, i.e.
 the multiplication of an induction variable in line 18 (gint = j * 3) is
 changed to addition, a new temporary iTemp17 is allocated and assigned
 a initial value, a constant 3 is then added for each iteration of the loop.
 The compiler does not change the multiplication
\begin_inset LatexCommand \index{Multiplication}

\end_inset

 in line 17 however since the processor does support an 8 * 8 bit multiplication.
\newline

Note the dead code elimination
\begin_inset LatexCommand \index{Dead-code elimination}

\end_inset

 optimization eliminated the dead assignments in line 7 & 8 to I and sum
 respectively.
\newline

\end_layout

\begin_layout Standard

\size footnotesize
Sample.c (5:1:0:0) _entry($9) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv 
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:4:53:0) preHeaderLbl0($11) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
 * int}[r2]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:6:5:1) _whilecontinue_0($1) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
 int}[r0]]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
 * int}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
 * int}[DPTR]]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
}[r2 r3]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
 * int}[r0] + 0x2 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:16:20:1) goto _whilecontinue_0($1)
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(11:17:21:0)_whilebreak_0($3) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:20:54:0)preHeaderLbl1($13) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:24:26:1)_forcond_0($4) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
 < 0xa {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
 + ITemp21 [lr21:38]{short}[r4]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
 * 0x3 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
 + iTemp15 [lr29:30]{short}[r1]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
 r0]- 0x3 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
int}[r7 r0]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
 + 0x1 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
 r6]- 0x1 {short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(19:38:47:1) goto _forcond_0($4)
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(19:39:48:0)_forbreak_0($7) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
 + ITemp11 [lr19:40]{short}[r3]
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(20:42:51:0)_return($8) :
\end_layout

\begin_layout Standard

\size footnotesize
Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
\size default

\newline

\newline
Finally the code generated for this function:
\newline

\end_layout

\begin_layout Standard

\size footnotesize
.area DSEG (DATA)
\end_layout

\begin_layout Standard

\size footnotesize
_p::
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
.ds 2
\end_layout

\begin_layout Standard

\size footnotesize
_gint::
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
.ds 2
\end_layout

\begin_layout Standard

\size footnotesize
; sample.c 5
\end_layout

\begin_layout Standard

\size footnotesize
; ----------------------------------------------
\end_layout

\begin_layout Standard

\size footnotesize
; function function
\end_layout

\begin_layout Standard

\size footnotesize
; ----------------------------------------------
\end_layout

\begin_layout Standard

\size footnotesize
_function:
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp0 [lr3:5]{_near * int}[r2] = recv 
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r2,dpl
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov ar0,r2
\end_layout

\begin_layout Standard

\size footnotesize
;_whilecontinue_0($1) :
\end_layout

\begin_layout Standard

\size footnotesize
00101$:
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
\end_layout

\begin_layout Standard

\size footnotesize
; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov ar2,@r0
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
inc r0
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov ar3,@r0
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
dec r0
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r2
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
orl a,r3
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
jz 00103$
\end_layout

\begin_layout Standard

\size footnotesize
00114$:
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov dpl,_p
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov dph,(_p + 1)
\end_layout

\begin_layout Standard

\size footnotesize
; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,#0x02
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
add a,_p
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov _p,a
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
clr a
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
addc a,(_p + 1)
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov (_p + 1),a
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
movx a,@dptr
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r2,a
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
inc dptr
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
movx a,@dptr
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r3,a
\end_layout

\begin_layout Standard

\size footnotesize
; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov @r0,ar2
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
inc r0
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov @r0,ar3
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp6 [lr5:16]{_near * int}[r0] = 
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp6 [lr5:16]{_near * int}[r0] + 
\end_layout

\begin_layout Standard

\size footnotesize
; 0x2 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
inc r0
\end_layout

\begin_layout Standard

\size footnotesize
; goto _whilecontinue_0($1)
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
sjmp 00101$
\end_layout

\begin_layout Standard

\size footnotesize
; _whilebreak_0($3) :
\end_layout

\begin_layout Standard

\size footnotesize
00103$:
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r2,#0x00
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r3,#0x00
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r4,#0x00
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r5,#0x0A
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r6,#0x00
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r7,#0x1E
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r0,#0x00
\end_layout

\begin_layout Standard

\size footnotesize
; _forcond_0($4) :
\end_layout

\begin_layout Standard

\size footnotesize
00104$:
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
\end_layout

\begin_layout Standard

\size footnotesize
; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
clr c
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r4
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
xrl a,#0x80
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
subb a,#0x8a
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
jnc 00107$
\end_layout

\begin_layout Standard

\size footnotesize
00115$:
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] + 
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp21 [lr21:38]{short}[r4]
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r4
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
add a,r2
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r2,a
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov b,#0x03
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r4
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mul ab
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r1,a
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] + 
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp15 [lr29:30]{short}[r1]
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
add a,r3
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r3,a
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r7
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
add a,#0xfd
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r7,a
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r0
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
addc a,#0xff
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov r0,a
\end_layout

\begin_layout Standard

\size footnotesize
; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r7
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
add a,_gint
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov _gint,a
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r0
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
addc a,(_gint + 1)
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov (_gint + 1),a
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
inc r4
\end_layout

\begin_layout Standard

\size footnotesize
; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
dec r5
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
cjne r5,#0xff,00104$
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
dec r6
\end_layout

\begin_layout Standard

\size footnotesize
; goto _forcond_0($4)
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
sjmp 00104$
\end_layout

\begin_layout Standard

\size footnotesize
; _forbreak_0($7) :
\end_layout

\begin_layout Standard

\size footnotesize
00107$:
\end_layout

\begin_layout Standard

\size footnotesize
; ret iTemp24 [lr40:41]{short}
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov a,r3
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
add a,r2
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
mov dpl,a
\end_layout

\begin_layout Standard

\size footnotesize
; _return($8) :
\end_layout

\begin_layout Standard

\size footnotesize
00108$:
\end_layout

\begin_layout Standard

\size footnotesize
\InsetSpace ~
\InsetSpace ~
ret
\newline

\end_layout

\begin_layout Section
A few words about basic block successors, predecessors and dominators
\end_layout

\begin_layout Standard
Successors are basic blocks
\begin_inset LatexCommand \index{Basic blocks}

\end_inset

 that might execute after this basic block.
\newline
Predecessors are basic blocks
 that might execute before reaching this basic block.
\newline
Dominators are basic
 blocks that WILL execute before reaching this basic block.
\newline

\end_layout

\begin_layout Standard
[basic block 1]
\end_layout

\begin_layout Standard
if (something)
\end_layout

\begin_layout Standard
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
[basic block 2]
\end_layout

\begin_layout Standard
else
\end_layout

\begin_layout Standard
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
[basic block 3]
\end_layout

\begin_layout Standard
[basic block 4]
\newline

\end_layout

\begin_layout Standard
a) succList of [BB2] = [BB4], of [BB3] = [BB4], of [BB1] = [BB2,BB3]
\end_layout

\begin_layout Standard
b) predList of [BB2] = [BB1], of [BB3] = [BB1], of [BB4] = [BB2,BB3]
\end_layout

\begin_layout Standard
c) domVect of [BB4] = BB1 ...
 here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
 was executed.
\end_layout

\begin_layout Chapter
Acknowledgments
\end_layout

\begin_layout Standard
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/#Who}

\end_inset


\newline

\newline

\emph on
Thanks to all the other volunteer developers who have helped with coding,
 testing, web-page creation, distribution sets, etc.
 You know who you are :-)
\emph default

\newline

\newline

\emph on
Thanks to Sourceforge 
\begin_inset LatexCommand \url{http://www.sf.net}

\end_inset

 which has hosted the project since 1999 and donates significant download
 bandwidth.
\emph default

\newline

\newline

\emph on
Also thanks to all SDCC Distributed Compile Farm members for donating CPU
 cycles and bandwidth for snapshot builds.
\newline

\end_layout

\begin_layout Standard
This document was initially written by Sandeep Dutta
\end_layout

\begin_layout Standard
All product names mentioned herein may be trademarks
\begin_inset LatexCommand \index{Trademarks}

\end_inset

 of their respective companies.
 
\end_layout

\begin_layout Section*
Alphabetical index
\end_layout

\begin_layout Standard
To avoid confusion, the installation and building options for SDCC itself
 (chapter 2) are not part of the index.
\end_layout

\begin_layout Standard
\begin_inset LatexCommand \printindex{}

\end_inset


\end_layout

\end_body
\end_document
