ppu.cpp

著名SFC模拟器Snes9x的源代码。

    case 0x421e:
    case 0x421f:
	// Joypad values (read-only)
	return;

    case 0x4300:
    case 0x4310:
    case 0x4320:
    case 0x4330:
    case 0x4340:
    case 0x4350:
    case 0x4360:
    case 0x4370:
	d = (Address >> 4) & 0x7;
	DMA[d].TransferDirection = (byte & 128) != 0 ? 1 : 0;
	DMA[d].HDMAIndirectAddressing = (byte & 64) != 0 ? 1 : 0;
	DMA[d].AAddressDecrement = (byte & 16) != 0 ? 1 : 0;
	DMA[d].AAddressFixed = (byte & 8) != 0 ? 1 : 0;
	DMA[d].TransferMode = (byte & 7);
	break;

    case 0x4301:
    case 0x4311:
    case 0x4321:
    case 0x4331:
    case 0x4341:
    case 0x4351:
    case 0x4361:
    case 0x4371:
	DMA[((Address >> 4) & 0x7)].BAddress = byte;
	break;

    case 0x4302:
    case 0x4312:
    case 0x4322:
    case 0x4332:
    case 0x4342:
    case 0x4352:
    case 0x4362:
    case 0x4372:
	d = (Address >> 4) & 0x7;
	DMA[d].AAddress &= 0xFF00;
	DMA[d].AAddress |= byte;
	break;

    case 0x4303:
    case 0x4313:
    case 0x4323:
    case 0x4333:
    case 0x4343:
    case 0x4353:
    case 0x4363:
    case 0x4373:
	d = (Address >> 4) & 0x7;
	DMA[d].AAddress &= 0xFF;
	DMA[d].AAddress |= byte << 8;
	break;

    case 0x4304:
    case 0x4314:
    case 0x4324:
    case 0x4334:
    case 0x4344:
    case 0x4354:
    case 0x4364:
    case 0x4374:
	DMA[((Address >> 4) & 0x7)].ABank = byte;
	break;

    case 0x4305:
    case 0x4315:
    case 0x4325:
    case 0x4335:
    case 0x4345:
    case 0x4355:
    case 0x4365:
    case 0x4375:
	d = (Address >> 4) & 0x7;
	DMA[d].TransferBytes &= 0xFF00;
	DMA[d].TransferBytes |= byte;
	DMA[d].IndirectAddress &= 0xff00;
	DMA[d].IndirectAddress |= byte;
	break;

    case 0x4306:
    case 0x4316:
    case 0x4326:
    case 0x4336:
    case 0x4346:
    case 0x4356:
    case 0x4366:
    case 0x4376:
	d = (Address >> 4) & 0x7;
	DMA[d].TransferBytes &= 0xFF;
	DMA[d].TransferBytes |= byte << 8;
	DMA[d].IndirectAddress &= 0xff;
	DMA[d].IndirectAddress |= byte << 8;
	break;

    case 0x4307:
    case 0x4317:
    case 0x4327:
    case 0x4337:
    case 0x4347:
    case 0x4357:
    case 0x4367:
    case 0x4377:
	DMA[d = ((Address >> 4) & 0x7)].IndirectBank = byte;
	break;

    case 0x4308:
    case 0x4318:
    case 0x4328:
    case 0x4338:
    case 0x4348:
    case 0x4358:
    case 0x4368:
    case 0x4378:
	d = (Address >> 4) & 7;
	DMA[d].Address &= 0xff00;
	DMA[d].Address |= byte;
	break;

    case 0x4309:
    case 0x4319:
    case 0x4329:
    case 0x4339:
    case 0x4349:
    case 0x4359:
    case 0x4369:
    case 0x4379:
	d = (Address >> 4) & 0x7;
	DMA[d].Address &= 0xff;
	DMA[d].Address |= byte << 8;
	break;

    case 0x430A:
    case 0x431A:
    case 0x432A:
    case 0x433A:
    case 0x434A:
    case 0x435A:
    case 0x436A:
    case 0x437A:
	d = (Address >> 4) & 0x7;
	DMA[d].LineCount = byte & 0x7f;
	DMA[d].Repeat = !(byte & 0x80);
	break;

    case 0x4800:
    case 0x4801:
    case 0x4802:
    case 0x4803:
	break;

    case 0x4804:
    case 0x4805:
    case 0x4806:
    case 0x4807:
	S9xSetSDD1MemoryMap (Address - 0x4804, byte & 7);
	break;
    default:
#ifdef DEBUGGER
	missing.unknowncpu_write = Address;
	if (Settings.TraceUnknownRegisters)
	{
	    sprintf (String, "Unknown register write: $%02X->$%04X\n",
		     byte, Address);
	    S9xMessage (S9X_TRACE, S9X_PPU_TRACE, String);
	}
#endif
	break;
    }
    Memory.FillRAM [Address] = byte;
}

/**********************************************************************************************/
/* S9xGetCPU()                                                                                   */
/* This function retrieves a CPU/DMA Register                                                 */
/**********************************************************************************************/
uint8 S9xGetCPU (uint16 Address)
{
    uint8 byte;

    if (Address < 0x4200)
    {
#ifdef VAR_CYCLES
	CPU.Cycles += ONE_CYCLE;
#endif
	switch (Address)
	{
	// Secret of the Evermore
	case 0x4000:
	case 0x4001:
	    return (0x40);

	case 0x4016:
	{
	    if (Memory.FillRAM [0x4016] & 1)
	    {
		if ((!Settings.SwapJoypads &&
		     IPPU.Controller == SNES_MOUSE_SWAPPED) ||
		    (Settings.SwapJoypads &&
		     IPPU.Controller == SNES_MOUSE))
		{
		    if (++PPU.MouseSpeed [0] > 2)
			PPU.MouseSpeed [0] = 0;
		}
		return (0);
	    }
		
	    int ind = Settings.SwapJoypads ? 1 : 0;
	    byte = IPPU.Joypads[ind] >> (PPU.Joypad1ButtonReadPos ^ 15);
	    PPU.Joypad1ButtonReadPos++;
	    return (byte & 1);
	}
	case 0x4017:
        {
	    if (Memory.FillRAM [0x4016] & 1)
	    {
		// MultiPlayer5 adaptor is only allowed to be plugged into port 2
		switch (IPPU.Controller)
		{
		case SNES_MULTIPLAYER5:
		    return (2);
		case SNES_MOUSE_SWAPPED:
		    if (Settings.SwapJoypads && ++PPU.MouseSpeed [0] > 2)
			PPU.MouseSpeed [0] = 0;
		    break;
		    
		case SNES_MOUSE:
		    if (!Settings.SwapJoypads && ++PPU.MouseSpeed [0] > 2)
			PPU.MouseSpeed [0] = 0;
		    break;
		}
		return (0x00);
	    }

	    int ind = Settings.SwapJoypads ? 0 : 1;

	    if (IPPU.Controller == SNES_MULTIPLAYER5)
	    {
		if (Memory.FillRAM [0x4201] & 0x80)
		{
		    byte = ((IPPU.Joypads[ind] >> (PPU.Joypad2ButtonReadPos ^ 15)) & 1) |
			    (((IPPU.Joypads[2] >> (PPU.Joypad2ButtonReadPos ^ 15)) & 1) << 1);
		    PPU.Joypad2ButtonReadPos++;
		    return (byte);
		}
		else
		{
		    byte = ((IPPU.Joypads[3] >> (PPU.Joypad3ButtonReadPos ^ 15)) & 1) |
			    (((IPPU.Joypads[4] >> (PPU.Joypad3ButtonReadPos ^ 15)) & 1) << 1);
		    PPU.Joypad3ButtonReadPos++;
		    return (byte);
		}
	    }
	    return ((IPPU.Joypads[ind] >> (PPU.Joypad2ButtonReadPos++ ^ 15)) & 1);
        }
	default:
#ifdef DEBUGGER
	    missing.unknowncpu_read = Address;
	    if (Settings.TraceUnknownRegisters)
	    {
		sprintf (String, "Unknown register read: $%04X\n", Address);
		S9xMessage (S9X_TRACE, S9X_PPU_TRACE, String);
	    }
#endif
	    break;
	}
	return (Memory.FillRAM [Address]);
    }
    else
    switch (Address)
    {
	// BS Dynami Tracer! needs to be able to check if NMIs are enabled
	// already, otherwise the game locks up.
    case 0x4200:
	// NMI, h & v timers and joypad reading enable
    case 0x4201:
	// I/O port (output - write only?)
    case 0x4202:
    case 0x4203:
	// Multiplier and multiplicand (write)
    case 0x4204:
    case 0x4205:
    case 0x4206:
	// Divisor and dividend (write)
	return (Memory.FillRAM[Address]);
    case 0x4207:
	return (uint8)(PPU.IRQHBeamPos);
    case 0x4208:
	return (PPU.IRQHBeamPos >> 8);
    case 0x4209:
	return (uint8)(PPU.IRQVBeamPos);
    case 0x420a:
	return (PPU.IRQVBeamPos >> 8);
    case 0x420b:
	// General purpose DMA enable
	// Super Formation Soccer 95 della Serie A UCC Xaqua requires this
	// register should not always return zero.
	// .. But Aero 2 waits until this register goes zero..
	// Just keep toggling the value for now in the hope that it breaks
	// the game out of its wait loop...
	Memory.FillRAM [0x420b] = !Memory.FillRAM [0x420b];
	return (Memory.FillRAM [0x420b]);
    case 0x420c:
	// H-DMA enable
	return (IPPU.HDMA);
    case 0x420d:
	// Cycle speed 0 - 2.68Mhz, 1 - 3.58Mhz (banks 0x80 +)
	return (Memory.FillRAM[Address]);
    case 0x420e:
    case 0x420f:
	// --->>> Unknown
	return (Memory.FillRAM[Address]);
    case 0x4210:
#ifdef CPU_SHUTDOWN
	CPU.WaitAddress = CPU.PCAtOpcodeStart;
#endif	
	byte = Memory.FillRAM[0x4210];
	Memory.FillRAM[0x4210] = 0;
	return (byte);
    case 0x4211:
	byte = (CPU.IRQActive & (PPU_V_BEAM_IRQ_SOURCE | PPU_H_BEAM_IRQ_SOURCE)) ? 0x80 : 0;
	// Super Robot Wars Ex ROM bug requires this.
	byte |= CPU.Cycles >= Settings.HBlankStart ? 0x40 : 0;
	CLEAR_IRQ_SOURCE (PPU_V_BEAM_IRQ_SOURCE | PPU_H_BEAM_IRQ_SOURCE);
	return (byte);
//    case 0x4200:
    case 0x4212:
	// V-blank, h-blank and joypads being read flags (read-only)
#ifdef CPU_SHUTDOWN
	CPU.WaitAddress = CPU.PCAtOpcodeStart;
#endif
	return (REGISTER_4212());
    case 0x4213:
	// I/O port input
    case 0x4214:
    case 0x4215:
	// Quotient of divide result
    case 0x4216:
    case 0x4217:
	// Multiplcation result (for multiply) or remainder of
	// divison.
	return (Memory.FillRAM[Address]);
    case 0x4218:
    case 0x4219:
    case 0x421a:
    case 0x421b:
    case 0x421c:
    case 0x421d:
    case 0x421e:
    case 0x421f:
	// Joypads 1-4 button and direction state.
	return (Memory.FillRAM [Address]);

    case 0x4300:
    case 0x4310:
    case 0x4320:
    case 0x4330:
    case 0x4340:
    case 0x4350:
    case 0x4360:
    case 0x4370:
	// DMA direction, address type, fixed flag,
	return (Memory.FillRAM[Address]);

    case 0x4301:
    case 0x4311:
    case 0x4321:
    case 0x4331:
    case 0x4341:
    case 0x4351:
    case 0x4361:
    case 0x4371:
	return (Memory.FillRAM[Address]);

    case 0x4302:
    case 0x4312:
    case 0x4322:
    case 0x4332:
    case 0x4342:
    case 0x4352:
    case 0x4362:
    case 0x4372:
	return (Memory.FillRAM[Address]);

    case 0x4303:
    case 0x4313:
    case 0x4323:
    case 0x4333:
    case 0x4343:
    case 0x4353:
    case 0x4363:
    case 0x4373:
	return (Memory.FillRAM[Address]);

    case 0x4304:
    case 0x4314:
    case 0x4324:
    case 0x4334:
    case 0x4344:
    case 0x4354:
    case 0x4364:
    case 0x4374:
	return (Memory.FillRAM[Address]);

    case 0x4305:
    case 0x4315:
    case 0x4325:
    case 0x4335:
    case 0x4345:
    case 0x4355:
    case 0x4365:
    case 0x4375:
	return (Memory.FillRAM[Address]);

    case 0x4306:
    case 0x4316:
    case 0x4326:
    case 0x4336:
    case 0x4346:
    case 0x4356:
    case 0x4366:
    case 0x4376:
	return (Memory.FillRAM[Address]);

    case 0x4307:
    case 0x4317:
    case 0x4327:
    case 0x4337:
    case 0x4347:
    case 0x4357:
    case 0x4367:
    case 0x4377:
	return (DMA[(Address >> 4) & 7].IndirectBank);

    case 0x4308:
    case 0x4318:
    case 0x4328:
    case 0x4338:
    case 0x4348:
    case 0x4358:
    case 0x4368:
    case 0x4378:
	return (Memory.FillRAM[Address]);

    case 0x4309:
    case 0x4319:
    case 0x4329:
    case 0x4339:
    case 0x4349:
    case 0x4359:
    case 0x4369:
    case 0x4379:
	return (Memory.FillRAM[Address]);

    case 0x430A:
    case 0x431A:
    case 0x432A:
    case 0x433A:
    case 0x434A:
    case 0x435A:
    case 0x436A:
    case 0x437A:
    {
	int d = (Address & 0x70) >> 4;
	if (IPPU.HDMA & (1 << d))
	{
	    return (DMA[d].LineCount);
	}
	return (Memory.FillRAM[Address]);
    }
    default:
#ifdef DEBUGGER
	missing.unknowncpu_read = Address;
	if (Settings.TraceUnknownRegisters)
	{
	    sprintf (String, "Unknown register read: $%04X\n", Address);
	    S9xMessage (S9X_TRACE, S9X_PPU_TRACE, String);
	}
	    
#endif
	break;
    }
    return (Memory.FillRAM[Address]);
}

void S9xResetPPU ()
{
    PPU.BGMode = 0;
    PPU.BG3Priority = 0;
    PPU.Brightness = 0;
    PPU.VMA.High = 0;
    PPU.VMA.Increment = 1;
    PPU.VMA.Address = 0;
    PPU.VMA.FullGraphicCount = 0;
    PPU.VMA.Shift = 0;

    for (uint8 B = 0; B != 4; B++)
    {
	PPU.BG[B].SCBase = 0;
	PPU.BG[B].VOffset = 0;
	PPU.BG[B].HOffset = 0;
	PPU.BG[B].BGSize = 0;
	PPU.BG[B].NameBase = 0;
	PPU.BG[B].SCSize = 0;

	PPU.ClipCounts[B] = 0;
	PPU.ClipWindowOverlapLogic [B] = CLIP_OR;
	PPU.ClipWindow1Enable[B] = FALSE;
	PPU.ClipWindow2Enable[B] = FALSE;
	PPU.ClipWindow1Inside[B] = TRUE;