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THE ATARI 6502 DISASSEMBLER

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Features of DIS6502

DIS6502 lets you disassemble

- Atari binary files on your hard disk,
- Atari binary files in .ATR/.XFD disk images,
- Boot sectors in .ATR/.XFD disk images,
- Any part of any sectors in .ATR/.XFD disk images,
- Spy data which is explained in "SPY disks" chapter.

A binary file contains one or several segments. A segment is a memory area and is identified by a start address and a length. When you load a binary file into the disassembler, the segment list is displayed into the upper left listbox. When you click on one of these segments, you see the dump in another listbox. This listbox shows all the bytes of the selected segments in hexadecimal and in ASCII/ATASCII format. You have also the disassembly listing on a right listbox.

Once you have loaded, for example, a binary file, DIS6502 offers you full access to its menu:

The different menus are:

- File,
- Select,
- Labels,
- Tools,
- Options,
- Help,

Let's review each menu

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File Menu

New clears all the segments loaded in memory.

Open binary file... loads an Atari binary file from your hard disk. This file must have the binary header ($FF $FF) to be recognized.

Open disk image file... loads an Atari binary file from .ATR/.XFD disk images. Only DOS 2.5 disks are supported. The disk can be a single or enhanced density disk.

Open disk image boot... loads boot sectors from .ATR/.XFD disk images. Boot sectors are considered to be 128 bytes long.

Open disk image sectors... loads any part of any sectors from .ATR/.XFD disk images. All densities/sizes are allowed: single, enhanced, double, quad or even larger (hard disk)

Open spy disk image data... loads data captured with a SPY disk.

Save disassembly listing... saves on your hard disk the listing generated by DI6502.

Load workspace... loads your work where you left it when you saved it with "Save workspace...". Without this option, each time you run the program, you start disassembling from scratch. Now you can set byte type, save workspace, and come back later in DIS6502 to continue working on the disassembly.

Save workspace... saves your work on your hard disk so you resume it later. This option does not save Assembler format. You have to do it yourself with another menu.

Exit quits DIS6502. BE CAREFUL: It doesn't ask you to save your work if you didn't do it.

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Select Menu

Select all selects all the bytes in the dump window.

Select sprites... lets the user search for the sprites in the selected segment. This dialog box is explained in "Viewing Sprites" chapter.

Find... can be used to find a HEX string or an ASCII string in the dump window. This lets you find the first occurence of a byte pattern in the selected segment or in all the segments.

Find next is used to find next byte pattern. This menu has a short key (F3) to get the next pattern with just one keystroke.

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Labels Menu

Clear all deletes all the user labels that you have defined.

Edit... lets you add/delete/modify a label that will be used in the disassembly listing.

Load... loads all the user labels from an ASCII file.

Save... saves all the user labels in an ASCII file that you can edit with NOTEPAD for example.

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Tools Menu

Merge segments looks at start and end address of each segment and try to find consecutive segments. If DIS6502 finds 2 consecutive segments, it merges them into a single segment.

Write boot disk... writes the selected segment as boot sectors. DIS6502 asks the user the load address and the init address to be able to write the header of the boot sectors.

Prepare spy disk... writes/modifies information for a SPY session. See "Using SPY Disk" chapter.

Disk image to PC transfer... lets the user extract a file from a disk image or write a file from hard disk to a .ATR/.XFD disk image. See "ATARI-PC File Transfer" chapter.

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Options Menu

Sreen display toggles between ASCII and screen (ANTIC) display in the dump window.

No disassembly toggles the start of the disassembly process. If "No disassembly" is checked, the disassembly process only takes place when a binary file is loaded. If this option is not checked (this is the default), disassembly is done each time a byte type is set or each time Assembler format is changed. Checking this menu is usefull when you need to do many changes without being disturbed by the disassembly process.

Output format... lets you choose the number of WORDs per line, the number of BYTEs per line and the number of characters per string.

Assembler format... customizes DIS6502 to meet your assembler syntax. "See Output Customization" chapter.

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Help Menu

About... displays version of DIS6502.