/*****************************************************************************

    h6280.c - Portable HuC6280 emulator

    Copyright (c) 1999, 2000 Bryan McPhail, mish@tendril.co.uk

    This source code is based (with permission!) on the 6502 emulator by
    Juergen Buchmueller.  It is released as part of the Mame emulator project.
    Let me know if you intend to use this code in any other project.


    NOTICE:

    This code is around 99% complete!  Several things are unimplemented,
    some due to lack of time, some due to lack of documentation, mainly
    due to lack of programs using these features.

    csh, csl opcodes are not supported.
    set opcode and T flag behaviour are not supported.

    I am unsure if instructions like SBC take an extra cycle when used in
    decimal mode.  I am unsure if flag B is set upon execution of rti.

    Cycle counts should be quite accurate, illegal instructions are assumed
    to take two cycles.


    Changelog, version 1.02:
        JMP + indirect X (0x7c) opcode fixed.
        SMB + RMB opcodes fixed in disassembler.
        change_pc function calls removed.
        TSB & TRB now set flags properly.
        BIT opcode altered.

    Changelog, version 1.03:
        Swapped IRQ mask for IRQ1 & IRQ2 (thanks Yasuhiro)

    Changelog, version 1.04, 28/9/99-22/10/99:
        Adjusted RTI (thanks Karl)
        TST opcodes fixed in disassembler (missing break statements in a case!).
        TST behaviour fixed.
        SMB/RMB/BBS/BBR fixed in disassembler.

    Changelog, version 1.05, 8/12/99-16/12/99:
        Added CAB's timer implementation (note: irq ack & timer reload are changed).
        Fixed STA IDX.
        Fixed B flag setting on BRK.
        Assumed CSH & CSL to take 2 cycles each.

        Todo:  Performance could be improved by precalculating timer fire position.

    Changelog, version 1.06, 4/5/00 - last opcode bug found?
        JMP indirect was doing a EAL++; instead of EAD++; - Obviously causing
        a corrupt read when L = 0xff!  This fixes Bloody Wolf and Trio The Punch!

    Changelog, version 1.07, 3/9/00:
        Changed timer to be single shot - fixes Crude Buster music in level 1.

******************************************************************************/

#include "memory.h"
#include "cpuintrf.h"
#include "mamedbg.h"
#include "h6280.h"

#include <stdio.h>
#include <string.h>

extern FILE * errorlog;

static UINT8 reg_layout[] = {
	H6280_PC, H6280_S, H6280_P, H6280_A, H6280_X, H6280_Y, -1,
	H6280_IRQ_MASK, H6280_TIMER_STATE, H6280_NMI_STATE, H6280_IRQ1_STATE, H6280_IRQ2_STATE, H6280_IRQT_STATE,
#ifdef MAME_DEBUG
	-1,
	H6280_M1, H6280_M2, H6280_M3, H6280_M4, -1,
	H6280_M5, H6280_M6, H6280_M7, H6280_M8,
#endif
	0
};

/* Layout of the debugger windows x,y,w,h */
static UINT8 win_layout[] = {
	25, 0,55, 4,	/* register window (top rows) */
	 0, 0,24,22,	/* disassembler window (left colums) */
	25, 5,55, 8,	/* memory #1 window (right, upper middle) */
	25,14,55, 8,	/* memory #2 window (right, lower middle) */
	 0,23,80, 1,	/* command line window (bottom rows) */
};

static int 	h6280_ICount = 0;

/****************************************************************************
 * The 6280 registers.
 ****************************************************************************/
typedef struct
{
	PAIR  ppc;			/* previous program counter */
    PAIR  pc;           /* program counter */
    PAIR  sp;           /* stack pointer (always 100 - 1FF) */
    PAIR  zp;           /* zero page address */
    PAIR  ea;           /* effective address */
    UINT8 a;            /* Accumulator */
    UINT8 x;            /* X index register */
    UINT8 y;            /* Y index register */
    UINT8 p;            /* Processor status */
    UINT8 mmr[8];       /* Hu6280 memory mapper registers */
    UINT8 irq_mask;     /* interrupt enable/disable */
    UINT8 timer_status; /* timer status */
	UINT8 timer_ack;	/* timer acknowledge */
    int timer_value;    /* timer interrupt */
    int timer_load;		/* reload value */
	int extra_cycles;	/* cycles used taking an interrupt */
    int nmi_state;
    int irq_state[3];
    int (*irq_callback)(int irqline);

#if LAZY_FLAGS
    int NZ;             /* last value (lazy N and Z flag) */
#endif

}   h6280_Regs;

static  h6280_Regs  h6280;

#ifdef  MAME_DEBUG /* Need some public segmentation registers for debugger */
UINT8	H6280_debug_mmr[8];
#endif

static void set_irq_line(int irqline, int state);

/* include the macros */
#include "h6280ops.h"

/* include the opcode macros, functions and function pointer tables */
#include "tblh6280.c"

/*****************************************************************************/
static void h6280_init(void)
{
}

static void h6280_reset(void *param)
{
	int i;

	/* wipe out the h6280 structure */
	memset(&h6280, 0, sizeof(h6280_Regs));

	/* set I and Z flags */
	P = _fI | _fZ;

    /* stack starts at 0x01ff */
	h6280.sp.d = 0x1ff;

    /* read the reset vector into PC */
	PCL = RDMEM(H6280_RESET_VEC);
	PCH = RDMEM((H6280_RESET_VEC+1));

	/* timer off by default */
	h6280.timer_status=0;
	h6280.timer_ack=1;

    /* clear pending interrupts */
	for (i = 0; i < 3; i++)
		h6280.irq_state[i] = CLEAR_LINE;
}

static void h6280_exit(void)
{
	/* nothing */
}

static int h6280_execute(int cycles)
{
	int in,lastcycle,deltacycle;
	h6280_ICount = cycles;

	/* Subtract cycles used for taking an interrupt */
	h6280_ICount -= h6280.extra_cycles;
	h6280.extra_cycles = 0;
	lastcycle = h6280_ICount;

	/* Execute instructions */
	do
    {
		h6280.ppc = h6280.pc;

#ifdef  MAME_DEBUG
	 	{
			if (mame_debug)
			{
				/* Copy the segmentation registers for debugger to use */
				int i;
				for (i=0; i<8; i++)
					H6280_debug_mmr[i]=h6280.mmr[i];

				MAME_Debug();
			}
		}
#endif

		/* Execute 1 instruction */
		in=RDOP();
		PCW++;
		insnh6280[in]();

		/* Check internal timer */
		if(h6280.timer_status)
		{
			deltacycle = lastcycle - h6280_ICount;
			h6280.timer_value -= deltacycle;
			if(h6280.timer_value<=0 && h6280.timer_ack==1)
			{
				h6280.timer_ack=h6280.timer_status=0;
				set_irq_line(2,ASSERT_LINE);
			}
		}
		lastcycle = h6280_ICount;

		/* If PC has not changed we are stuck in a tight loop, may as well finish */
		if( h6280.pc.d == h6280.ppc.d )
		{
			if (h6280_ICount > 0) h6280_ICount=0;
			h6280.extra_cycles = 0;
			return cycles;
		}

	} while (h6280_ICount > 0);

	/* Subtract cycles used for taking an interrupt */
	h6280_ICount -= h6280.extra_cycles;
	h6280.extra_cycles = 0;

	return cycles - h6280_ICount;
}

static void h6280_get_context (void *dst)
{
	if( dst )
		*(h6280_Regs*)dst = h6280;
}

static void h6280_set_context (void *src)
{
	if( src )
		h6280 = *(h6280_Regs*)src;
}


/*****************************************************************************/

static void set_irq_line(int irqline, int state)
{
	if (irqline == INPUT_LINE_NMI)
	{
		if (h6280.nmi_state == state) return;
		h6280.nmi_state = state;
		if (state != CLEAR_LINE)
	    {
			DO_INTERRUPT(H6280_NMI_VEC);
		}
	}
	else if (irqline < 3)
	{
	    h6280.irq_state[irqline] = state;

		/* If line is cleared, just exit */
		if (state == CLEAR_LINE) return;

		/* Check if interrupts are enabled and the IRQ mask is clear */
		CHECK_IRQ_LINES;
	}
}


static offs_t h6280_dasm(char *buffer, offs_t pc)
{
#ifdef MAME_DEBUG
    return Dasm6280(buffer,pc);
#else
	sprintf( buffer, "$%02X", cpu_readop(pc) );
	return 1;
#endif
}

/*****************************************************************************/

READ8_HANDLER( H6280_irq_status_r )
{
	int status;

	switch (offset)
	{
		case 0: /* Read irq mask */
			return h6280.irq_mask;

		case 1: /* Read irq status */
			status=0;
			if(h6280.irq_state[1]!=CLEAR_LINE) status|=1; /* IRQ 2 */
			if(h6280.irq_state[0]!=CLEAR_LINE) status|=2; /* IRQ 1 */
			if(h6280.irq_state[2]!=CLEAR_LINE) status|=4; /* TIMER */
			return status;
	}

	return 0;
}

WRITE8_HANDLER( H6280_irq_status_w )
{
	switch (offset)
	{
		case 0: /* Write irq mask */
			h6280.irq_mask=data&0x7;
			CHECK_IRQ_LINES;
			break;

		case 1: /* Timer irq ack - timer is reloaded here */
			h6280.timer_value = h6280.timer_load;
			h6280.timer_ack=1; /* Timer can't refire until ack'd */
			break;
	}
}

READ8_HANDLER( H6280_timer_r )
{
	switch (offset) {
		case 0: /* Counter value */
			return (h6280.timer_value/1024)&127;

		case 1: /* Read counter status */
			return h6280.timer_status;
	}

	return 0;
}

WRITE8_HANDLER( H6280_timer_w )
{
	switch (offset) {
		case 0: /* Counter preload */
			h6280.timer_load=h6280.timer_value=((data&127)+1)*1024;
			return;

		case 1: /* Counter enable */
			if(data&1)
			{	/* stop -> start causes reload */
				if(h6280.timer_status==0) h6280.timer_value=h6280.timer_load;
			}
			h6280.timer_status=data&1;
			return;
	}
}

/*****************************************************************************/

/**************************************************************************
 * Generic set_info
 **************************************************************************/

static void h6280_set_info(UINT32 state, union cpuinfo *info)
{
	switch (state)
	{
		/* --- the following bits of info are set as 64-bit signed integers --- */
		case CPUINFO_INT_INPUT_STATE + 0:			set_irq_line(0, info->i);					break;
		case CPUINFO_INT_INPUT_STATE + 1:			set_irq_line(1, info->i);					break;
		case CPUINFO_INT_INPUT_STATE + 2:			set_irq_line(2, info->i);					break;
		case CPUINFO_INT_INPUT_STATE + INPUT_LINE_NMI:set_irq_line(INPUT_LINE_NMI, info->i);		break;

		case CPUINFO_INT_PC:
		case CPUINFO_INT_REGISTER + H6280_PC:		PCW = info->i;								break;
		case CPUINFO_INT_SP:
		case CPUINFO_INT_REGISTER + H6280_S:		S = info->i;								break;
		case CPUINFO_INT_REGISTER + H6280_P:		P = info->i;								break;
		case CPUINFO_INT_REGISTER + H6280_A:		A = info->i;								break;
		case CPUINFO_INT_REGISTER + H6280_X:		X = info->i;								break;
		case CPUINFO_INT_REGISTER + H6280_Y:		Y = info->i;								break;
		case CPUINFO_INT_REGISTER + H6280_IRQ_MASK: h6280.irq_mask = info->i; CHECK_IRQ_LINES;	break;
		case CPUINFO_INT_REGISTER + H6280_TIMER_STATE: h6280.timer_status = info->i; 			break;
		case CPUINFO_INT_REGISTER + H6280_NMI_STATE: set_irq_line( INPUT_LINE_NMI, info->i ); 	break;
		case CPUINFO_INT_REGISTER + H6280_IRQ1_STATE: set_irq_line( 0, info->i ); 				break;
		case CPUINFO_INT_REGISTER + H6280_IRQ2_STATE: set_irq_line( 1, info->i ); 				break;
		case CPUINFO_INT_REGISTER + H6280_IRQT_STATE: set_irq_line( 2, info->i ); 				break;
#ifdef MAME_DEBUG
		case CPUINFO_INT_REGISTER + H6280_M1:		h6280.mmr[0] = info->i;						break;
		case CPUINFO_INT_REGISTER + H6280_M2:		h6280.mmr[1] = info->i;						break;
		case CPUINFO_INT_REGISTER + H6280_M3:		h6280.mmr[2] = info->i;						break;
		case CPUINFO_INT_REGISTER + H6280_M4:		h6280.mmr[3] = info->i;						break;
		case CPUINFO_INT_REGISTER + H6280_M5:		h6280.mmr[4] = info->i;						break;
		case CPUINFO_INT_REGISTER + H6280_M6:		h6280.mmr[5] = info->i;						break;
		case CPUINFO_INT_REGISTER + H6280_M7:		h6280.mmr[6] = info->i;						break;
		case CPUINFO_INT_REGISTER + H6280_M8:		h6280.mmr[7] = info->i;						break;
#endif
		/* --- the following bits of info are set as pointers to data or functions --- */
		case CPUINFO_PTR_IRQ_CALLBACK:				h6280.irq_callback = info->irqcallback;		break;
	}
}



/**************************************************************************
 * Generic get_info
 **************************************************************************/

void h6280_get_info(UINT32 state, union cpuinfo *info)
{
	switch (state)
	{
		/* --- the following bits of info are returned as 64-bit signed integers --- */
		case CPUINFO_INT_CONTEXT_SIZE:					info->i = sizeof(h6280);				break;
		case CPUINFO_INT_INPUT_LINES:					info->i = 3;							break;
		case CPUINFO_INT_DEFAULT_IRQ_VECTOR:			info->i = 0;							break;
		case CPUINFO_INT_ENDIANNESS:					info->i = CPU_IS_LE;					break;
		case CPUINFO_INT_CLOCK_DIVIDER:					info->i = 1;							break;
		case CPUINFO_INT_MIN_INSTRUCTION_BYTES:			info->i = 1;							break;
		case CPUINFO_INT_MAX_INSTRUCTION_BYTES:			info->i = 3;							break;
		case CPUINFO_INT_MIN_CYCLES:					info->i = 2;							break;
		case CPUINFO_INT_MAX_CYCLES:					info->i = 17 + 6*65536;					break;

		case CPUINFO_INT_DATABUS_WIDTH + ADDRESS_SPACE_PROGRAM:	info->i = 8;					break;
		case CPUINFO_INT_ADDRBUS_WIDTH + ADDRESS_SPACE_PROGRAM: info->i = 21;					break;
		case CPUINFO_INT_ADDRBUS_SHIFT + ADDRESS_SPACE_PROGRAM: info->i = 0;					break;
		case CPUINFO_INT_DATABUS_WIDTH + ADDRESS_SPACE_DATA:	info->i = 0;					break;
		case CPUINFO_INT_ADDRBUS_WIDTH + ADDRESS_SPACE_DATA: 	info->i = 0;					break;
		case CPUINFO_INT_ADDRBUS_SHIFT + ADDRESS_SPACE_DATA: 	info->i = 0;					break;
		case CPUINFO_INT_DATABUS_WIDTH + ADDRESS_SPACE_IO:		info->i = 8;					break;
		case CPUINFO_INT_ADDRBUS_WIDTH + ADDRESS_SPACE_IO: 		info->i = 2;					break;
		case CPUINFO_INT_ADDRBUS_SHIFT + ADDRESS_SPACE_IO: 		info->i = 0;					break;

		case CPUINFO_INT_INPUT_STATE + 0:				info->i = h6280.irq_state[0];			break;
		case CPUINFO_INT_INPUT_STATE + 1:				info->i = h6280.irq_state[1];			break;
		case CPUINFO_INT_INPUT_STATE + 2:				info->i = h6280.irq_state[2];			break;
		case CPUINFO_INT_INPUT_STATE + INPUT_LINE_NMI:	info->i = h6280.nmi_state; 				break;

		case CPUINFO_INT_PREVIOUSPC:					info->i = h6280.ppc.d;					break;

		case CPUINFO_INT_PC:
		case CPUINFO_INT_REGISTER + H6280_PC:			info->i = PCD;							break;
		case CPUINFO_INT_SP:
		case CPUINFO_INT_REGISTER + H6280_S:			info->i = S;							break;
		case CPUINFO_INT_REGISTER + H6280_P:			info->i = P;							break;
		case CPUINFO_INT_REGISTER + H6280_A:			info->i = A;							break;
		case CPUINFO_INT_REGISTER + H6280_X:			info->i = X;							break;
		case CPUINFO_INT_REGISTER + H6280_Y:			info->i = Y;							break;
		case CPUINFO_INT_REGISTER + H6280_IRQ_MASK:		info->i = h6280.irq_mask;				break;
		case CPUINFO_INT_REGISTER + H6280_TIMER_STATE:	info->i = h6280.timer_status;			break;
		case CPUINFO_INT_REGISTER + H6280_NMI_STATE:	info->i = h6280.nmi_state;				break;
		case CPUINFO_INT_REGISTER + H6280_IRQ1_STATE:	info->i = h6280.irq_state[0];			break;
		case CPUINFO_INT_REGISTER + H6280_IRQ2_STATE:	info->i = h6280.irq_state[1];			break;
		case CPUINFO_INT_REGISTER + H6280_IRQT_STATE:	info->i = h6280.irq_state[2];			break;
#ifdef MAME_DEBUG
		case CPUINFO_INT_REGISTER + H6280_M1:			info->i = h6280.mmr[0];					break;
		case CPUINFO_INT_REGISTER + H6280_M2:			info->i = h6280.mmr[1];					break;
		case CPUINFO_INT_REGISTER + H6280_M3:			info->i = h6280.mmr[2];					break;
		case CPUINFO_INT_REGISTER + H6280_M4:			info->i = h6280.mmr[3];					break;
		case CPUINFO_INT_REGISTER + H6280_M5:			info->i = h6280.mmr[4];					break;
		case CPUINFO_INT_REGISTER + H6280_M6:			info->i = h6280.mmr[5];					break;
		case CPUINFO_INT_REGISTER + H6280_M7:			info->i = h6280.mmr[6];					break;
		case CPUINFO_INT_REGISTER + H6280_M8:			info->i = h6280.mmr[7];					break;
#endif

		/* --- the following bits of info are returned as pointers to data or functions --- */
		case CPUINFO_PTR_SET_INFO:						info->setinfo = h6280_set_info;			break;
		case CPUINFO_PTR_GET_CONTEXT:					info->getcontext = h6280_get_context;	break;
		case CPUINFO_PTR_SET_CONTEXT:					info->setcontext = h6280_set_context;	break;
		case CPUINFO_PTR_INIT:							info->init = h6280_init;				break;
		case CPUINFO_PTR_RESET:							info->reset = h6280_reset;				break;
		case CPUINFO_PTR_EXIT:							info->exit = h6280_exit;				break;
		case CPUINFO_PTR_EXECUTE:						info->execute = h6280_execute;			break;
		case CPUINFO_PTR_BURN:							info->burn = NULL;						break;
		case CPUINFO_PTR_DISASSEMBLE:					info->disassemble = h6280_dasm;			break;
		case CPUINFO_PTR_IRQ_CALLBACK:					info->irqcallback = h6280.irq_callback;	break;
		case CPUINFO_PTR_INSTRUCTION_COUNTER:			info->icount = &h6280_ICount;			break;
		case CPUINFO_PTR_REGISTER_LAYOUT:				info->p = reg_layout;					break;
		case CPUINFO_PTR_WINDOW_LAYOUT:					info->p = win_layout;					break;

		/* --- the following bits of info are returned as NULL-terminated strings --- */
		case CPUINFO_STR_NAME:							strcpy(info->s = cpuintrf_temp_str(), "HuC6280"); break;
		case CPUINFO_STR_CORE_FAMILY:					strcpy(info->s = cpuintrf_temp_str(), "Hudsonsoft 6280"); break;
		case CPUINFO_STR_CORE_VERSION:					strcpy(info->s = cpuintrf_temp_str(), "1.07"); break;
		case CPUINFO_STR_CORE_FILE:						strcpy(info->s = cpuintrf_temp_str(), __FILE__); break;
		case CPUINFO_STR_CORE_CREDITS:					strcpy(info->s = cpuintrf_temp_str(), "Copyright (c) 1999, 2000 Bryan McPhail, mish@tendril.co.uk"); break;

		case CPUINFO_STR_FLAGS:
			sprintf(info->s = cpuintrf_temp_str(), "%c%c%c%c%c%c%c%c",
				h6280.p & 0x80 ? 'N':'.',
				h6280.p & 0x40 ? 'V':'.',
				h6280.p & 0x20 ? 'R':'.',
				h6280.p & 0x10 ? 'B':'.',
				h6280.p & 0x08 ? 'D':'.',
				h6280.p & 0x04 ? 'I':'.',
				h6280.p & 0x02 ? 'Z':'.',
				h6280.p & 0x01 ? 'C':'.');
			break;

		case CPUINFO_STR_REGISTER + H6280_PC:			sprintf(info->s = cpuintrf_temp_str(), "PC:%04X", h6280.pc.d); break;
        case CPUINFO_STR_REGISTER + H6280_S:			sprintf(info->s = cpuintrf_temp_str(), "S:%02X", h6280.sp.b.l); break;
        case CPUINFO_STR_REGISTER + H6280_P:			sprintf(info->s = cpuintrf_temp_str(), "P:%02X", h6280.p); break;
        case CPUINFO_STR_REGISTER + H6280_A:			sprintf(info->s = cpuintrf_temp_str(), "A:%02X", h6280.a); break;
		case CPUINFO_STR_REGISTER + H6280_X:			sprintf(info->s = cpuintrf_temp_str(), "X:%02X", h6280.x); break;
		case CPUINFO_STR_REGISTER + H6280_Y:			sprintf(info->s = cpuintrf_temp_str(), "Y:%02X", h6280.y); break;
		case CPUINFO_STR_REGISTER + H6280_IRQ_MASK:		sprintf(info->s = cpuintrf_temp_str(), "IM:%02X", h6280.irq_mask); break;
		case CPUINFO_STR_REGISTER + H6280_TIMER_STATE:	sprintf(info->s = cpuintrf_temp_str(), "TMR:%02X", h6280.timer_status); break;
		case CPUINFO_STR_REGISTER + H6280_NMI_STATE:	sprintf(info->s = cpuintrf_temp_str(), "NMI:%X", h6280.nmi_state); break;
		case CPUINFO_STR_REGISTER + H6280_IRQ1_STATE:	sprintf(info->s = cpuintrf_temp_str(), "IRQ1:%X", h6280.irq_state[0]); break;
		case CPUINFO_STR_REGISTER + H6280_IRQ2_STATE:	sprintf(info->s = cpuintrf_temp_str(), "IRQ2:%X", h6280.irq_state[1]); break;
		case CPUINFO_STR_REGISTER + H6280_IRQT_STATE:	sprintf(info->s = cpuintrf_temp_str(), "IRQT:%X", h6280.irq_state[2]); break;
#ifdef MAME_DEBUG
		case CPUINFO_STR_REGISTER + H6280_M1:			sprintf(info->s = cpuintrf_temp_str(), "M1:%02X", h6280.mmr[0]); break;
		case CPUINFO_STR_REGISTER + H6280_M2:			sprintf(info->s = cpuintrf_temp_str(), "M2:%02X", h6280.mmr[1]); break;
		case CPUINFO_STR_REGISTER + H6280_M3:			sprintf(info->s = cpuintrf_temp_str(), "M3:%02X", h6280.mmr[2]); break;
		case CPUINFO_STR_REGISTER + H6280_M4:			sprintf(info->s = cpuintrf_temp_str(), "M4:%02X", h6280.mmr[3]); break;
		case CPUINFO_STR_REGISTER + H6280_M5:			sprintf(info->s = cpuintrf_temp_str(), "M5:%02X", h6280.mmr[4]); break;
		case CPUINFO_STR_REGISTER + H6280_M6:			sprintf(info->s = cpuintrf_temp_str(), "M6:%02X", h6280.mmr[5]); break;
		case CPUINFO_STR_REGISTER + H6280_M7:			sprintf(info->s = cpuintrf_temp_str(), "M7:%02X", h6280.mmr[6]); break;
		case CPUINFO_STR_REGISTER + H6280_M8:			sprintf(info->s = cpuintrf_temp_str(), "M8:%02X", h6280.mmr[7]); break;
#endif
	}
}
