snes9x/fxemu.cpp

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/*****************************************************************************\
Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
This file is licensed under the Snes9x License.
For further information, consult the LICENSE file in the root directory.
\*****************************************************************************/
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#include "snes9x.h"
#include "memmap.h"
#include "fxinst.h"
#include "fxemu.h"
static void FxReset (struct FxInfo_s *);
static void fx_readRegisterSpace (void);
static void fx_writeRegisterSpace (void);
static void fx_updateRamBank (uint8);
static void fx_dirtySCBR (void);
static bool8 fx_checkStartAddress (void);
static uint32 FxEmulate (uint32);
static void FxCacheWriteAccess (uint16);
static void FxFlushCache (void);
void S9xInitSuperFX (void)
{
memset((uint8 *) &GSU, 0, sizeof(struct FxRegs_s));
}
void S9xResetSuperFX (void)
{
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// FIXME: Snes9x only runs the SuperFX at the end of every line.
// 5823405 is a magic number that seems to work for most games.
SuperFX.speedPerLine = (uint32) (5823405 * ((1.0 / (float) Memory.ROMFramesPerSecond) / ((float) (Timings.V_Max))));
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SuperFX.oneLineDone = FALSE;
SuperFX.vFlags = 0;
CPU.IRQExternal = FALSE;
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FxReset(&SuperFX);
}
void S9xSetSuperFX (uint8 byte, uint16 address)
{
switch (address)
{
case 0x3030:
if ((Memory.FillRAM[0x3030] ^ byte) & FLG_G)
{
Memory.FillRAM[0x3030] = byte;
if (byte & FLG_G)
{
if (!SuperFX.oneLineDone)
{
S9xSuperFXExec();
SuperFX.oneLineDone = TRUE;
}
}
else
FxFlushCache();
}
else
Memory.FillRAM[0x3030] = byte;
break;
case 0x3031:
Memory.FillRAM[0x3031] = byte;
break;
case 0x3033:
Memory.FillRAM[0x3033] = byte;
break;
case 0x3034:
Memory.FillRAM[0x3034] = byte & 0x7f;
break;
case 0x3036:
Memory.FillRAM[0x3036] = byte & 0x7f;
break;
case 0x3037:
Memory.FillRAM[0x3037] = byte;
break;
case 0x3038:
Memory.FillRAM[0x3038] = byte;
fx_dirtySCBR();
break;
case 0x3039:
Memory.FillRAM[0x3039] = byte;
break;
case 0x303a:
Memory.FillRAM[0x303a] = byte;
break;
case 0x303b:
break;
case 0x303c:
Memory.FillRAM[0x303c] = byte;
fx_updateRamBank(byte);
break;
case 0x303f:
Memory.FillRAM[0x303f] = byte;
break;
case 0x301f:
Memory.FillRAM[0x301f] = byte;
Memory.FillRAM[0x3000 + GSU_SFR] |= FLG_G;
if (!SuperFX.oneLineDone)
{
S9xSuperFXExec();
SuperFX.oneLineDone = TRUE;
}
break;
default:
Memory.FillRAM[address] = byte;
if (address >= 0x3100)
FxCacheWriteAccess(address);
break;
}
}
uint8 S9xGetSuperFX (uint16 address)
{
uint8 byte;
byte = Memory.FillRAM[address];
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if (address == 0x3031)
{
CPU.IRQExternal = FALSE;
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Memory.FillRAM[0x3031] = byte & 0x7f;
}
return (byte);
}
void S9xSuperFXExec (void)
{
if ((Memory.FillRAM[0x3000 + GSU_SFR] & FLG_G) && (Memory.FillRAM[0x3000 + GSU_SCMR] & 0x18) == 0x18)
{
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FxEmulate(((Memory.FillRAM[0x3000 + GSU_CLSR] & 1) ? (SuperFX.speedPerLine * 8 / 3) : SuperFX.speedPerLine) * Settings.SuperFXClockMultiplier / 100);
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uint16 GSUStatus = Memory.FillRAM[0x3000 + GSU_SFR] | (Memory.FillRAM[0x3000 + GSU_SFR + 1] << 8);
if ((GSUStatus & (FLG_G | FLG_IRQ)) == FLG_IRQ)
CPU.IRQExternal = TRUE;
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}
}
static void FxReset (struct FxInfo_s *psFxInfo)
{
// Clear all internal variables
memset((uint8 *) &GSU, 0, sizeof(struct FxRegs_s));
// Set default registers
GSU.pvSreg = GSU.pvDreg = &R0;
// Set RAM and ROM pointers
GSU.pvRegisters = psFxInfo->pvRegisters;
GSU.nRamBanks = psFxInfo->nRamBanks;
GSU.pvRam = psFxInfo->pvRam;
GSU.nRomBanks = psFxInfo->nRomBanks;
GSU.pvRom = psFxInfo->pvRom;
GSU.vPrevScreenHeight = ~0;
GSU.vPrevMode = ~0;
// The GSU can't access more than 2mb (16mbits)
if (GSU.nRomBanks > 0x20)
GSU.nRomBanks = 0x20;
// Clear FxChip register space
memset(GSU.pvRegisters, 0, 0x300);
// Set FxChip version Number
GSU.pvRegisters[0x3b] = 0;
// Make ROM bank table
for (int i = 0; i < 256; i++)
{
uint32 b = i & 0x7f;
if (b >= 0x40)
{
if (GSU.nRomBanks > 1)
b %= GSU.nRomBanks;
else
b &= 1;
GSU.apvRomBank[i] = &GSU.pvRom[b << 16];
}
else
{
b %= GSU.nRomBanks * 2;
GSU.apvRomBank[i] = &GSU.pvRom[(b << 16) + 0x200000];
}
}
// Make RAM bank table
for (int i = 0; i < 4; i++)
{
GSU.apvRamBank[i] = &GSU.pvRam[(i % GSU.nRamBanks) << 16];
GSU.apvRomBank[0x70 + i] = GSU.apvRamBank[i];
}
// Start with a nop in the pipe
GSU.vPipe = 0x01;
// Set pointer to GSU cache
GSU.pvCache = &GSU.pvRegisters[0x100];
fx_readRegisterSpace();
}
static void fx_readRegisterSpace (void)
{
static uint32 avHeight[] = { 128, 160, 192, 256 };
static uint32 avMult[] = { 16, 32, 32, 64 };
uint8 *p;
int n;
GSU.vErrorCode = 0;
// Update R0-R15
p = GSU.pvRegisters;
for (int i = 0; i < 16; i++)
{
GSU.avReg[i] = *p++;
GSU.avReg[i] += ((uint32) (*p++)) << 8;
}
// Update other registers
p = GSU.pvRegisters;
GSU.vStatusReg = (uint32) p[GSU_SFR];
GSU.vStatusReg |= ((uint32) p[GSU_SFR + 1]) << 8;
GSU.vPrgBankReg = (uint32) p[GSU_PBR];
GSU.vRomBankReg = (uint32) p[GSU_ROMBR];
GSU.vRamBankReg = ((uint32) p[GSU_RAMBR]) & (FX_RAM_BANKS - 1);
GSU.vCacheBaseReg = (uint32) p[GSU_CBR];
GSU.vCacheBaseReg |= ((uint32) p[GSU_CBR + 1]) << 8;
// Update status register variables
GSU.vZero = !(GSU.vStatusReg & FLG_Z);
GSU.vSign = (GSU.vStatusReg & FLG_S) << 12;
GSU.vOverflow = (GSU.vStatusReg & FLG_OV) << 16;
GSU.vCarry = (GSU.vStatusReg & FLG_CY) >> 2;
// Set bank pointers
GSU.pvRamBank = GSU.apvRamBank[GSU.vRamBankReg & 0x3];
GSU.pvRomBank = GSU.apvRomBank[GSU.vRomBankReg];
GSU.pvPrgBank = GSU.apvRomBank[GSU.vPrgBankReg];
// Set screen pointers
GSU.pvScreenBase = &GSU.pvRam[USEX8(p[GSU_SCBR]) << 10];
n = (int) (!!(p[GSU_SCMR] & 0x04));
n |= ((int) (!!(p[GSU_SCMR] & 0x20))) << 1;
GSU.vScreenHeight = GSU.vScreenRealHeight = avHeight[n];
GSU.vMode = p[GSU_SCMR] & 0x03;
if (n == 3)
GSU.vScreenSize = (256 / 8) * (256 / 8) * 32;
else
GSU.vScreenSize = (GSU.vScreenHeight / 8) * (256 / 8) * avMult[GSU.vMode];
if (GSU.vPlotOptionReg & 0x10) // OBJ Mode (for drawing into sprites)
GSU.vScreenHeight = 256;
if (GSU.pvScreenBase + GSU.vScreenSize > GSU.pvRam + (GSU.nRamBanks * 65536))
GSU.pvScreenBase = GSU.pvRam + (GSU.nRamBanks * 65536) - GSU.vScreenSize;
GSU.pfPlot = fx_PlotTable[GSU.vMode];
GSU.pfRpix = fx_PlotTable[GSU.vMode + 5];
fx_OpcodeTable[0x04c] = GSU.pfPlot;
fx_OpcodeTable[0x14c] = GSU.pfRpix;
fx_OpcodeTable[0x24c] = GSU.pfPlot;
fx_OpcodeTable[0x34c] = GSU.pfRpix;
fx_computeScreenPointers();
//fx_backupCache();
}
static void fx_writeRegisterSpace (void)
{
uint8 *p;
p = GSU.pvRegisters;
for (int i = 0; i < 16; i++)
{
*p++ = (uint8) GSU.avReg[i];
*p++ = (uint8) (GSU.avReg[i] >> 8);
}
// Update status register
if (USEX16(GSU.vZero) == 0)
SF(Z);
else
CF(Z);
if (GSU.vSign & 0x8000)
SF(S);
else
CF(S);
if (GSU.vOverflow >= 0x8000 || GSU.vOverflow < -0x8000)
SF(OV);
else
CF(OV);
if (GSU.vCarry)
SF(CY);
else
CF(CY);
p = GSU.pvRegisters;
p[GSU_SFR] = (uint8) GSU.vStatusReg;
p[GSU_SFR + 1] = (uint8) (GSU.vStatusReg >> 8);
p[GSU_PBR] = (uint8) GSU.vPrgBankReg;
p[GSU_ROMBR] = (uint8) GSU.vRomBankReg;
p[GSU_RAMBR] = (uint8) GSU.vRamBankReg;
p[GSU_CBR] = (uint8) GSU.vCacheBaseReg;
p[GSU_CBR + 1] = (uint8) (GSU.vCacheBaseReg >> 8);
//fx_restoreCache();
}
// Update RamBankReg and RAM Bank pointer
static void fx_updateRamBank (uint8 byte)
{
// Update BankReg and Bank pointer
GSU.vRamBankReg = (uint32) byte & (FX_RAM_BANKS - 1);
GSU.pvRamBank = GSU.apvRamBank[byte & 0x3];
}
// SCBR write seen. We need to update our cached screen pointers
static void fx_dirtySCBR (void)
{
GSU.vSCBRDirty = TRUE;
}
static bool8 fx_checkStartAddress (void)
{
// Check if we start inside the cache
if (GSU.bCacheActive && R15 >= GSU.vCacheBaseReg && R15 < (GSU.vCacheBaseReg + 512))
return (TRUE);
/*
// Check if we're in an unused area
if (GSU.vPrgBankReg < 0x40 && R15 < 0x8000)
return (FALSE);
*/
if (GSU.vPrgBankReg >= 0x60 && GSU.vPrgBankReg <= 0x6f)
return (FALSE);
if (GSU.vPrgBankReg >= 0x74)
return (FALSE);
// Check if we're in RAM and the RAN flag is not set
if (GSU.vPrgBankReg >= 0x70 && GSU.vPrgBankReg <= 0x73 && !(SCMR & (1 << 3)))
return (FALSE);
// If not, we're in ROM, so check if the RON flag is set
if (!(SCMR & (1 << 4)))
return (FALSE);
return (TRUE);
}
// Execute until the next stop instruction
static uint32 FxEmulate (uint32 nInstructions)
{
uint32 vCount;
// Read registers and initialize GSU session
fx_readRegisterSpace();
// Check if the start address is valid
if (!fx_checkStartAddress())
{
CF(G);
fx_writeRegisterSpace();
/*
GSU.vIllegalAddress = (GSU.vPrgBankReg << 24) | R15;
return (FX_ERROR_ILLEGAL_ADDRESS);
*/
return (0);
}
// Execute GSU session
CF(IRQ);
/*
if (GSU.bBreakPoint)
vCount = fx_run_to_breakpoint(nInstructions);
else
*/
vCount = fx_run(nInstructions);
// Store GSU registers
fx_writeRegisterSpace();
// Check for error code
if (GSU.vErrorCode)
return (GSU.vErrorCode);
else
return (vCount);
}
void fx_computeScreenPointers (void)
{
if (GSU.vMode != GSU.vPrevMode || GSU.vPrevScreenHeight != GSU.vScreenHeight || GSU.vSCBRDirty)
{
GSU.vSCBRDirty = FALSE;
// Make a list of pointers to the start of each screen column
switch (GSU.vScreenHeight)
{
case 128:
switch (GSU.vMode)
{
case 0:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 4);
GSU.x[i] = i << 8;
}
break;
case 1:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 5);
GSU.x[i] = i << 9;
}
break;
case 2:
case 3:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 6);
GSU.x[i] = i << 10;
}
break;
}
break;
case 160:
switch (GSU.vMode)
{
case 0:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 4);
GSU.x[i] = (i << 8) + (i << 6);
}
break;
case 1:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 5);
GSU.x[i] = (i << 9) + (i << 7);
}
break;
case 2:
case 3:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 6);
GSU.x[i] = (i << 10) + (i << 8);
}
break;
}
break;
case 192:
switch (GSU.vMode)
{
case 0:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 4);
GSU.x[i] = (i << 8) + (i << 7);
}
break;
case 1:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 5);
GSU.x[i] = (i << 9) + (i << 8);
}
break;
case 2:
case 3:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + (i << 6);
GSU.x[i] = (i << 10) + (i << 9);
}
break;
}
break;
case 256:
switch (GSU.vMode)
{
case 0:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + ((i & 0x10) << 9) + ((i & 0xf) << 8);
GSU.x[i] = ((i & 0x10) << 8) + ((i & 0xf) << 4);
}
break;
case 1:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + ((i & 0x10) << 10) + ((i & 0xf) << 9);
GSU.x[i] = ((i & 0x10) << 9) + ((i & 0xf) << 5);
}
break;
case 2:
case 3:
for (int i = 0; i < 32; i++)
{
GSU.apvScreen[i] = GSU.pvScreenBase + ((i & 0x10) << 11) + ((i & 0xf) << 10);
GSU.x[i] = ((i & 0x10) << 10) + ((i & 0xf) << 6);
}
break;
}
break;
}
GSU.vPrevMode = GSU.vMode;
GSU.vPrevScreenHeight = GSU.vScreenHeight;
}
}
// Write access to the cache
static void FxCacheWriteAccess (uint16 vAddress)
{
/*
if (!GSU.bCacheActive)
{
uint8 v = GSU.pvCache[GSU.pvCache[vAddress & 0x1ff];
fx_setCache();
GSU.pvCache[GSU.pvCache[vAddress & 0x1ff] = v;
}
*/
if ((vAddress & 0x00f) == 0x00f)
GSU.vCacheFlags |= 1 << ((vAddress & 0x1f0) >> 4);
}
static void FxFlushCache (void)
{
GSU.vCacheFlags = 0;
GSU.vCacheBaseReg = 0;
GSU.bCacheActive = FALSE;
//GSU.vPipe = 0x1;
}
void fx_flushCache (void)
{
//fx_restoreCache();
GSU.vCacheFlags = 0;
GSU.bCacheActive = FALSE;
}
/*
static void fx_setCache (void)
{
uint32 c;
GSU.bCacheActive = TRUE;
GSU.pvRegisters[0x3e] &= 0xf0;
c = (uint32) GSU.pvRegisters[0x3e];
c |= ((uint32) GSU.pvRegisters[0x3f]) << 8;
if (c == GSU.vCacheBaseReg)
return;
GSU.vCacheBaseReg = c;
GSU.vCacheFlags = 0;
if (c < (0x10000 - 512))
{
const uint8 *t = &ROM(c);
memcpy(GSU.pvCache, t, 512);
}
else
{
const uint8 *t1, *t2;
uint32 i = 0x10000 - c;
t1 = &ROM(c);
t2 = &ROM(0);
memcpy(GSU.pvCache, t1, i);
memcpy(&GSU.pvCache[i], t2, 512 - i);
}
}
*/
/*
static void fx_backupCache (void)
{
uint32 v = GSU.vCacheFlags;
uint32 c = USEX16(GSU.vCacheBaseReg);
if (v)
{
for (int i = 0; i < 32; i++)
{
if (v & 1)
{
if (c < (0x10000 - 16))
{
uint8 *t = &GSU.pvPrgBank[c];
memcpy(&GSU.avCacheBackup[i << 4], t, 16);
memcpy(t, &GSU.pvCache[i << 4], 16);
}
else
{
uint8 *t1, *t2;
uint32 a = 0x10000 - c;
t1 = &GSU.pvPrgBank[c];
t2 = &GSU.pvPrgBank[0];
memcpy(&GSU.avCacheBackup[i << 4], t1, a);
memcpy(t1, &GSU.pvCache[i << 4], a);
memcpy(&GSU.avCacheBackup[(i << 4) + a], t2, 16 - a);
memcpy(t2, &GSU.pvCache[(i << 4) + a], 16 - a);
}
}
c = USEX16(c + 16);
v >>= 1;
}
}
}
*/
/*
static void fx_restoreCache()
{
uint32 v = GSU.vCacheFlags;
uint32 c = USEX16(GSU.vCacheBaseReg);
if (v)
{
for (int i = 0; i < 32; i++)
{
if (v & 1)
{
if (c < (0x10000 - 16))
{
uint8 *t = &GSU.pvPrgBank[c];
memcpy(t, &GSU.avCacheBackup[i << 4], 16);
memcpy(&GSU.pvCache[i << 4], t, 16);
}
else
{
uint8 *t1, *t2;
uint32 a = 0x10000 - c;
t1 = &GSU.pvPrgBank[c];
t2 = &GSU.pvPrgBank[0];
memcpy(t1, &GSU.avCacheBackup[i << 4], a);
memcpy(&GSU.pvCache[i << 4], t1, a);
memcpy(t2, &GSU.avCacheBackup[(i << 4) + a], 16 - a);
memcpy(&GSU.pvCache[(i << 4) + a], t2, 16 - a);
}
}
c = USEX16(c + 16);
v >>= 1;
}
}
}
*/
// Breakpoints
/*
static void FxBreakPointSet (uint32 vAddress)
{
GSU.bBreakPoint = TRUE;
GSU.vBreakPoint = USEX16(vAddress);
}
*/
/*
static void FxBreakPointClear (void)
{
GSU.bBreakPoint = FALSE;
}
*/
// Step by step execution
/*
static uint32 FxStepOver (uint32 nInstructions)
{
uint32 vCount;
fx_readRegisterSpace();
if (!fx_checkStartAddress())
{
CF(G);
#if 0
GSU.vIllegalAddress = (GSU.vPrgBankReg << 24) | R15;
return (FX_ERROR_ILLEGAL_ADDRESS);
#else
return (0);
#endif
}
if (PIPE >= 0xf0)
GSU.vStepPoint = USEX16(R15 + 3);
else
if ((PIPE >= 0x05 && PIPE <= 0x0f) || (PIPE >= 0xa0 && PIPE <= 0xaf))
GSU.vStepPoint = USEX16(R15 + 2);
else
GSU.vStepPoint = USEX16(R15 + 1);
vCount = fx_step_over(nInstructions);
fx_writeRegisterSpace();
if (GSU.vErrorCode)
return (GSU.vErrorCode);
else
return (vCount);
}
*/
// Errors
/*
static int FxGetErrorCode (void)
{
return (GSU.vErrorCode);
}
*/
/*
static int FxGetIllegalAddress (void)
{
return (GSU.vIllegalAddress);
}
*/
// Access to internal registers
/*
static uint32 FxGetColorRegister (void)
{
return (GSU.vColorReg & 0xff);
}
*/
/*
static uint32 FxGetPlotOptionRegister (void)
{
return (GSU.vPlotOptionReg & 0x1f);
}
*/
/*
static uint32 FxGetSourceRegisterIndex (void)
{
return (GSU.pvSreg - GSU.avReg);
}
*/
/*
static uint32 FxGetDestinationRegisterIndex (void)
{
return (GSU.pvDreg - GSU.avReg);
}
*/
// Get the byte currently in the pipe
/*
static uint8 FxPipe (void)
{
return (GSU.vPipe);
}
*/