sa1.cpp

著名SFC模拟器Snes9x的源代码。

/*
 * Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 *
 * (c) Copyright 1996 - 2001 Gary Henderson ([e-mail]) and
 *                           Jerremy Koot ([e-mail])
 *
 * Super FX C emulator code 
 * (c) Copyright 1997 - 1999 Ivar ([e-mail]) and
 *                           Gary Henderson.
 * Super FX assembler emulator code (c) Copyright 1998 zsKnight and _Demo_.
 *
 * DSP1 emulator code (c) Copyright 1998 Ivar, _Demo_ and Gary Henderson.
 * C4 asm and some C emulation code (c) Copyright 2000 zsKnight and _Demo_.
 * C4 C code (c) Copyright 2001 Gary Henderson ([e-mail]).
 *
 * DOS port code contains the works of other authors. See headers in
 * individual files.
 *
 * Snes9x homepage: www.snes9x.com
 *
 * Permission to use, copy, modify and distribute Snes9x in both binary and
 * source form, for non-commercial purposes, is hereby granted without fee,
 * providing that this license information and copyright notice appear with
 * all copies and any derived work.
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event shall the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Snes9x is freeware for PERSONAL USE only. Commercial users should
 * seek permission of the copyright holders first. Commercial use includes
 * charging money for Snes9x or software derived from Snes9x.
 *
 * The copyright holders request that bug fixes and improvements to the code
 * should be forwarded to them so everyone can benefit from the modifications
 * in future versions.
 *
 * Super NES and Super Nintendo Entertainment System are trademarks of
 * Nintendo Co., Limited and its subsidiary companies.
 */
#include "snes9x.h"
#include "ppu.h"
#include "cpuexec.h"

#include "sa1.h"

static void S9xSA1CharConv2 ();
static void S9xSA1DMA ();
static void S9xSA1ReadVariableLengthData (bool8 inc, bool8 no_shift);

void S9xSA1Init ()
{
    SA1.NMIActive = FALSE;
    SA1.IRQActive = FALSE;
    SA1.WaitingForInterrupt = FALSE;
    SA1.Waiting = FALSE;
    SA1.Flags = 0;
    SA1.Executing = FALSE;
    memset (&Memory.FillRAM [0x2200], 0, 0x200);
    Memory.FillRAM [0x2200] = 0x20;
    Memory.FillRAM [0x2220] = 0x00;
    Memory.FillRAM [0x2221] = 0x01;
    Memory.FillRAM [0x2222] = 0x02;
    Memory.FillRAM [0x2223] = 0x03;
    Memory.FillRAM [0x2228] = 0xff;
    SA1.op1 = 0;
    SA1.op2 = 0;
    SA1.arithmetic_op = 0;
    SA1.sum = 0;
    SA1.overflow = FALSE;
}

void S9xSA1Reset ()
{
    SA1Registers.PB = 0;
    SA1Registers.PC = Memory.FillRAM [0x2203] |
		      (Memory.FillRAM [0x2204] << 8);
    SA1Registers.D.W = 0;
    SA1Registers.DB = 0;
    SA1Registers.SH = 1;
    SA1Registers.SL = 0xFF;
    SA1Registers.XH = 0;
    SA1Registers.YH = 0;
    SA1Registers.P.W = 0;

    SA1.ShiftedPB = 0;
    SA1.ShiftedDB = 0;
    SA1SetFlags (MemoryFlag | IndexFlag | IRQ | Emulation);
    SA1ClearFlags (Decimal);

    SA1.WaitingForInterrupt = FALSE;
    SA1.PC = NULL;
    SA1.PCBase = NULL;
    S9xSA1SetPCBase (SA1Registers.PC);
    SA1.S9xOpcodes = S9xSA1OpcodesM1X1;

    S9xSA1UnpackStatus();
    S9xSA1FixCycles ();
    SA1.Executing = TRUE;
    SA1.BWRAM = Memory.SRAM;
    Memory.FillRAM [0x2225] = 0;
}

void S9xSA1SetBWRAMMemMap (uint8 val)
{
    int c;

    if (val & 0x80)
    {
	for (c = 0; c < 0x400; c += 16)
	{
	    SA1.Map [c + 6] = SA1.Map [c + 0x806] = (uint8 *) CMemory::MAP_BWRAM_BITMAP2;
	    SA1.Map [c + 7] = SA1.Map [c + 0x807] = (uint8 *) CMemory::MAP_BWRAM_BITMAP2;
	    SA1.WriteMap [c + 6] = SA1.WriteMap [c + 0x806] = (uint8 *) CMemory::MAP_BWRAM_BITMAP2;
	    SA1.WriteMap [c + 7] = SA1.WriteMap [c + 0x807] = (uint8 *) CMemory::MAP_BWRAM_BITMAP2;
	}
	SA1.BWRAM = Memory.SRAM + (val & 0x7f) * 0x2000 / 4;
    }
    else
    {
	for (c = 0; c < 0x400; c += 16)
	{
	    SA1.Map [c + 6] = SA1.Map [c + 0x806] = (uint8 *) CMemory::MAP_BWRAM;
	    SA1.Map [c + 7] = SA1.Map [c + 0x807] = (uint8 *) CMemory::MAP_BWRAM;
	    SA1.WriteMap [c + 6] = SA1.WriteMap [c + 0x806] = (uint8 *) CMemory::MAP_BWRAM;
	    SA1.WriteMap [c + 7] = SA1.WriteMap [c + 0x807] = (uint8 *) CMemory::MAP_BWRAM;
	}
	SA1.BWRAM = Memory.SRAM + (val & 7) * 0x2000;
    }
}

void S9xFixSA1AfterSnapshotLoad ()
{
    SA1.ShiftedPB = (uint32) SA1Registers.PB << 16;
    SA1.ShiftedDB = (uint32) SA1Registers.DB << 16;

    S9xSA1SetPCBase (SA1.ShiftedPB + SA1Registers.PC);
    S9xSA1UnpackStatus ();
    S9xSA1FixCycles ();
    SA1.VirtualBitmapFormat = (Memory.FillRAM [0x223f] & 0x80) ? 2 : 4;
    Memory.BWRAM = Memory.SRAM + (Memory.FillRAM [0x2224] & 7) * 0x2000;
    S9xSA1SetBWRAMMemMap (Memory.FillRAM [0x2225]);

    SA1.Waiting = (Memory.FillRAM [0x2200] & 0x60) != 0;
    SA1.Executing = !SA1.Waiting;
}

uint8 S9xSA1GetByte (uint32 address)
{
    uint8 *GetAddress = SA1.Map [(address >> MEMMAP_SHIFT) & MEMMAP_MASK];
    if (GetAddress >= (uint8 *) CMemory::MAP_LAST)
	return (*(GetAddress + (address & 0xffff)));

    switch ((int) GetAddress)
    {
    case CMemory::MAP_PPU:
	return (S9xGetSA1 (address & 0xffff));
    case CMemory::MAP_LOROM_SRAM:
    case CMemory::MAP_SA1RAM:
	return (*(Memory.SRAM + (address & 0xffff)));
    case CMemory::MAP_BWRAM:
	return (*(SA1.BWRAM + ((address & 0x7fff) - 0x6000)));
    case CMemory::MAP_BWRAM_BITMAP:
	address -= 0x600000;
	if (SA1.VirtualBitmapFormat == 2)
	    return ((Memory.SRAM [(address >> 2) & 0xffff] >> ((address & 3) << 1)) & 3);
	else
	    return ((Memory.SRAM [(address >> 1) & 0xffff] >> ((address & 1) << 2)) & 15);
    case CMemory::MAP_BWRAM_BITMAP2:
	address = (address & 0xffff) - 0x6000;
	if (SA1.VirtualBitmapFormat == 2)
	    return ((SA1.BWRAM [(address >> 2) & 0xffff] >> ((address & 3) << 1)) & 3);
	else
	    return ((SA1.BWRAM [(address >> 1) & 0xffff] >> ((address & 1) << 2)) & 15);

    case CMemory::MAP_DEBUG:
    default:
#ifdef DEBUGGER
//	printf ("R(B) %06x\n", address);
#endif

	return (0);
    }
}

uint16 S9xSA1GetWord (uint32 address)
{
    return (S9xSA1GetByte (address) | (S9xSA1GetByte (address + 1) << 8));
}

void S9xSA1SetByte (uint8 byte, uint32 address)
{
    uint8 *Setaddress = SA1.WriteMap [(address >> MEMMAP_SHIFT) & MEMMAP_MASK];

    if (Setaddress >= (uint8 *) CMemory::MAP_LAST)
    {
	*(Setaddress + (address & 0xffff)) = byte;
	return;
    }

    switch ((int) Setaddress)
    {
    case CMemory::MAP_PPU:
	S9xSetSA1 (byte, address & 0xffff);
	return;
    case CMemory::MAP_SA1RAM:
    case CMemory::MAP_LOROM_SRAM:
	*(Memory.SRAM + (address & 0xffff)) = byte;
	return;
    case CMemory::MAP_BWRAM:
	*(SA1.BWRAM + ((address & 0x7fff) - 0x6000)) = byte;
	return;
    case CMemory::MAP_BWRAM_BITMAP:
	address -= 0x600000;
	if (SA1.VirtualBitmapFormat == 2)
	{
	    uint8 *ptr = &Memory.SRAM [(address >> 2) & 0xffff];
	    *ptr &= ~(3 << ((address & 3) << 1));
	    *ptr |= (byte & 3) << ((address & 3) << 1);
	}
	else
	{
	    uint8 *ptr = &Memory.SRAM [(address >> 1) & 0xffff];
	    *ptr &= ~(15 << ((address & 1) << 2));
	    *ptr |= (byte & 15) << ((address & 1) << 2);
	}
	break;
    case CMemory::MAP_BWRAM_BITMAP2:
	address = (address & 0xffff) - 0x6000;
	if (SA1.VirtualBitmapFormat == 2)
	{
	    uint8 *ptr = &SA1.BWRAM [(address >> 2) & 0xffff];
	    *ptr &= ~(3 << ((address & 3) << 1));
	    *ptr |= (byte & 3) << ((address & 3) << 1);
	}
	else
	{
	    uint8 *ptr = &SA1.BWRAM [(address >> 1) & 0xffff];
	    *ptr &= ~(15 << ((address & 1) << 2));
	    *ptr |= (byte & 15) << ((address & 1) << 2);
	}
    default:
	return;
    }
}

void S9xSA1SetWord (uint16 Word, uint32 address)
{
    S9xSA1SetByte ((uint8) Word, address);
    S9xSA1SetByte ((uint8) (Word >> 8), address + 1);
}

void S9xSA1SetPCBase (uint32 address)
{
    uint8 *GetAddress = SA1.Map [(address >> MEMMAP_SHIFT) & MEMMAP_MASK];
    if (GetAddress >= (uint8 *) CMemory::MAP_LAST)
    {
	SA1.PCBase = GetAddress;
	SA1.PC = GetAddress + (address & 0xffff);
	return;
    }

    switch ((int) GetAddress)
    {
    case CMemory::MAP_PPU:
	SA1.PCBase = Memory.FillRAM - 0x2000;
	SA1.PC = SA1.PCBase + (address & 0xffff);
	return;
	
    case CMemory::MAP_CPU:
	SA1.PCBase = Memory.FillRAM - 0x4000;
	SA1.PC = SA1.PCBase + (address & 0xffff);
	return;
	
    case CMemory::MAP_DSP:
	SA1.PCBase = Memory.FillRAM - 0x6000;
	SA1.PC = SA1.PCBase + (address & 0xffff);
	return;
	
    case CMemory::MAP_SA1RAM:
    case CMemory::MAP_LOROM_SRAM:
	SA1.PCBase = Memory.SRAM;
	SA1.PC = SA1.PCBase + (address & 0xffff);
	return;

    case CMemory::MAP_BWRAM:
	SA1.PCBase = SA1.BWRAM - 0x6000;
	SA1.PC = SA1.PCBase + (address & 0xffff);
	return;
    case CMemory::MAP_HIROM_SRAM:
	SA1.PCBase = Memory.SRAM - 0x6000;
	SA1.PC = SA1.PCBase + (address & 0xffff);
	return;

    case CMemory::MAP_DEBUG:
#ifdef DEBUGGER
	printf ("SBP %06x\n", address);
#endif
	
    default:
    case CMemory::MAP_NONE:
	SA1.PCBase = Memory.RAM;
	SA1.PC = Memory.RAM + (address & 0xffff);
	return;
    }
}

void S9xSA1ExecuteDuringSleep ()
{
#if 0
    if (SA1.Executing)
    {
	while (CPU.Cycles < CPU.NextEvent)
	{
	    S9xSA1MainLoop ();
	    CPU.Cycles += TWO_CYCLES * 2;
	}
    }
#endif
}

void S9xSetSA1MemMap (uint32 which1, uint8 map)
{
    int c;
    int start = which1 * 0x100 + 0xc00;
    int start2 = which1 * 0x200;

    if (which1 >= 2)
	start2 += 0x400;

    for (c = 0; c < 0x100; c += 16)
    {
	uint8 *block = &Memory.ROM [(map & 7) * 0x100000 + (c << 12)];
	int i;

	for (i = c; i < c + 16; i++)
	    Memory.Map [start + i] = SA1.Map [start + i] = block;
    }
    
    for (c = 0; c < 0x200; c += 16)
    {
	uint8 *block = &Memory.ROM [(map & 7) * 0x100000 + (c << 11) - 0x8000];
	int i;

	for (i = c + 8; i < c + 16; i++)
	    Memory.Map [start2 + i] = SA1.Map [start2 + i] = block;
    }
}

uint8 S9xGetSA1 (uint32 address)
{
//	printf ("R: %04x\n", address);
    switch (address)
    {
    case 0x2300:
	return ((uint8) ((Memory.FillRAM [0x2209] & 0x5f) | 
		 (CPU.IRQActive & (SA1_IRQ_SOURCE | SA1_DMA_IRQ_SOURCE))));
    case 0x2301:
	return ((Memory.FillRAM [0x2200] & 0xf) |
		(Memory.FillRAM [0x2301] & 0xf0));
    case 0x2306:
	return ((uint8)  SA1.sum);
    case 0x2307:
	return ((uint8) (SA1.sum >>  8));
    case 0x2308:
	return ((uint8) (SA1.sum >> 16));
    case 0x2309:
	return ((uint8) (SA1.sum >> 24));
    case 0x230a:
	return ((uint8) (SA1.sum >> 32));
    case 0x230c:
	return (Memory.FillRAM [0x230c]);
    case 0x230d:
    {
	uint8 byte = Memory.FillRAM [0x230d];

	if (Memory.FillRAM [0x2258] & 0x80)
	{
	    S9xSA1ReadVariableLengthData (TRUE, FALSE);
	}
	return (byte);
    }
    default:	
//	printf ("R: %04x\n", address);
	break;
    }
    return (Memory.FillRAM [address]);
}

void S9xSetSA1 (uint8 byte, uint32 address)
{
//printf ("W: %02x -> %04x\n", byte, address);
    switch (address)
    {
    case 0x2200:
	SA1.Waiting = (byte & 0x60) != 0;
//	SA1.Executing = !SA1.Waiting && SA1.S9xOpcodes;

	if (!(byte & 0x20) && (Memory.FillRAM [0x2200] & 0x20))
	{
	    S9xSA1Reset ();
	}
	if (byte & 0x80)
	{
	    Memory.FillRAM [0x2301] |= 0x80;
	    if (Memory.FillRAM [0x220a] & 0x80)
	    {
		SA1.Flags |= IRQ_PENDING_FLAG;
		SA1.IRQActive |= SNES_IRQ_SOURCE;
		SA1.Executing = !SA1.Waiting && SA1.S9xOpcodes;
	    }
	}
	if (byte & 0x10)
	{
	    Memory.FillRAM [0x2301] |= 0x10;
#ifdef DEBUGGER
		printf ("###SA1 NMI\n");
#endif
	    if (Memory.FillRAM [0x220a] & 0x10)
	    {
	    }
	}
	break;

    case 0x2201:
	if (((byte ^ Memory.FillRAM [0x2201]) & 0x80) &&
	    (Memory.FillRAM [0x2300] & byte & 0x80))
	{
	    S9xSetIRQ (SA1_IRQ_SOURCE);
	}
	if (((byte ^ Memory.FillRAM [0x2201]) & 0x20) &&
	    (Memory.FillRAM [0x2300] & byte & 0x20))
	{
	    S9xSetIRQ (SA1_DMA_IRQ_SOURCE);
	}
	break;
    case 0x2202:
	if (byte & 0x80)
	{
	    Memory.FillRAM [0x2300] &= ~0x80;
	    S9xClearIRQ (SA1_IRQ_SOURCE);
	}
	if (byte & 0x20)
	{
	    Memory.FillRAM [0x2300] &= ~0x20;
	    S9xClearIRQ (SA1_DMA_IRQ_SOURCE);
	}