ppu.cpp

著名SFC模拟器Snes9x的源代码。

		    PPU.OAMAddr = 0;
		
	    }
	    PPU.OAMReadFlip ^= 1;
#ifdef DEBUGGER
	    missing.oam_read = 1;
#endif
	    return (byte);

	case 0x2139:
	    // Read vram low byte
#ifdef DEBUGGER
	    missing.vram_read = 1;
#endif
	    if (IPPU.FirstVRAMRead)
		byte = Memory.VRAM[PPU.VMA.Address << 1];
	    else
	    if (PPU.VMA.FullGraphicCount)
	    {
		uint32 addr = PPU.VMA.Address - 1;
		uint32 rem = addr & PPU.VMA.Mask1;
		uint32 address = (addr & ~PPU.VMA.Mask1) +
				 (rem >> PPU.VMA.Shift) +
				 ((rem & (PPU.VMA.FullGraphicCount - 1)) << 3);
		byte = Memory.VRAM [((address << 1) - 2) & 0xFFFF];
	    }
	    else
		byte = Memory.VRAM[((PPU.VMA.Address << 1) - 2) & 0xffff];

	    if (!PPU.VMA.High)
	    {
		PPU.VMA.Address += PPU.VMA.Increment;
		IPPU.FirstVRAMRead = FALSE;
	    }
	    break;
	case 0x213A:
	    // Read vram high byte
#ifdef DEBUGGER
	    missing.vram_read = 1;
#endif
	    if (IPPU.FirstVRAMRead)
		byte = Memory.VRAM[((PPU.VMA.Address << 1) + 1) & 0xffff];
	    else
	    if (PPU.VMA.FullGraphicCount)
	    {
		uint32 addr = PPU.VMA.Address - 1;
		uint32 rem = addr & PPU.VMA.Mask1;
		uint32 address = (addr & ~PPU.VMA.Mask1) +
				 (rem >> PPU.VMA.Shift) +
				 ((rem & (PPU.VMA.FullGraphicCount - 1)) << 3);
		byte = Memory.VRAM [((address << 1) - 1) & 0xFFFF];
	    }
	    else
		byte = Memory.VRAM[((PPU.VMA.Address << 1) - 1) & 0xFFFF];
	    if (PPU.VMA.High)
	    {
		PPU.VMA.Address += PPU.VMA.Increment;
		IPPU.FirstVRAMRead = FALSE;
	    }
	    break;

	case 0x213B:
	    // Read palette data
#ifdef DEBUGGER
	    missing.cgram_read = 1;
#endif
	    if (PPU.CGFLIPRead)
		byte = PPU.CGDATA [PPU.CGADD++] >> 8;
	    else
		byte = PPU.CGDATA [PPU.CGADD] & 0xff;

	    PPU.CGFLIPRead ^= 1;
	    return (byte);
	    
	case 0x213C:
	    // Horizontal counter value 0-339
#ifdef DEBUGGER
	    missing.h_counter_read = 1;
#endif
	    if (PPU.HBeamFlip)
		byte = PPU.HBeamPosLatched >> 8;
	    else
		byte = (uint8)PPU.HBeamPosLatched;
	    PPU.HBeamFlip ^= 1;
	    break;
	case 0x213D:
	    // Vertical counter value 0-262
#ifdef DEBUGGER
	    missing.v_counter_read = 1;
#endif
	    if (PPU.VBeamFlip)
		byte = PPU.VBeamPosLatched >> 8;
	    else
		byte = (uint8)PPU.VBeamPosLatched;
	    PPU.VBeamFlip ^= 1;
	    break;
	case 0x213E:
	    // PPU time and range over flags
	    return (0);
	case 0x213F:
	    // NTSC/PAL and which field flags
	    PPU.VBeamFlip = PPU.HBeamFlip = 0;
	    return ((Settings.PAL ? 0x10 : 0) | (Memory.FillRAM[0x213f] & 0xc0));

	case 0x2140: case 0x2141: case 0x2142: case 0x2143:
	case 0x2144: case 0x2145: case 0x2146: case 0x2147:
	case 0x2148: case 0x2149: case 0x214a: case 0x214b:
	case 0x214c: case 0x214d: case 0x214e: case 0x214f:
	case 0x2150: case 0x2151: case 0x2152: case 0x2153:
	case 0x2154: case 0x2155: case 0x2156: case 0x2157:
	case 0x2158: case 0x2159: case 0x215a: case 0x215b:
	case 0x215c: case 0x215d: case 0x215e: case 0x215f:
	case 0x2160: case 0x2161: case 0x2162: case 0x2163:
	case 0x2164: case 0x2165: case 0x2166: case 0x2167:
	case 0x2168: case 0x2169: case 0x216a: case 0x216b:
	case 0x216c: case 0x216d: case 0x216e: case 0x216f:
	case 0x2170: case 0x2171: case 0x2172: case 0x2173:
	case 0x2174: case 0x2175: case 0x2176: case 0x2177:
	case 0x2178: case 0x2179: case 0x217a: case 0x217b:
	case 0x217c: case 0x217d: case 0x217e: case 0x217f:
#ifdef SPCTOOL
	    return ((uint8) _SPCOutP [Address & 3]);
#else
    //	CPU.Flags |= DEBUG_MODE_FLAG;
#ifdef SPC700_SHUTDOWN	
	    IAPU.APUExecuting = Settings.APUEnabled;
	    IAPU.WaitCounter++;
#endif
	    if (Settings.APUEnabled)
	    {
#ifdef CPU_SHUTDOWN
//		CPU.WaitAddress = CPU.PCAtOpcodeStart;
#endif	
		return (APU.OutPorts [Address & 3]);
	    }

	    switch (Settings.SoundSkipMethod)
	    {
	    case 0:
	    case 1:
		CPU.BranchSkip = TRUE;
		break;
	    case 2:
		break;
	    case 3:
		CPU.BranchSkip = TRUE;
		break;
	    }
	    if (Address & 3 < 2)
	    {
		int r = rand ();
		if (r & 2)
		{
		    if (r & 4)
			return (Address & 3 == 1 ? 0xaa : 0xbb);
		    else
			return ((r >> 3) & 0xff);
		}
	    }
	    else
	    {
		int r = rand ();
		if (r & 2)
		    return ((r >> 3) & 0xff);
	    }
	    return (Memory.FillRAM[Address]);
#endif // SPCTOOL

	case 0x2180:
	    // Read WRAM
#ifdef DEBUGGER
	    missing.wram_read = 1;
#endif
	    byte = Memory.RAM [PPU.WRAM++];
	    PPU.WRAM &= 0x1FFFF;
	    break;
	case 0x2181:
	case 0x2182:
	case 0x2183:
	    return (Memory.FillRAM [Address]);
	case 0x2190:
	    return (1);
	}
    }
    else
    {
	if (Settings.SA1)
	    return (S9xGetSA1 (Address));

	if (Address <= 0x2fff || Address >= 0x3000 + 768)
	{
	    switch (Address)
	    {
	    case 0x21c2:
	        return (0x20);
	    case 0x21c3:
	        return (0);
	    case 0x2800:
		// For Dai Kaijyu Monogatari II
		if (Settings.SRTC)
		    return (S9xGetSRTC (Address));
		/*FALL*/
			    
	    default:
#ifdef DEBUGGER
	        missing.unknownppu_read = Address;
	        if (Settings.TraceUnknownRegisters)
		{
		    sprintf (String, "Unknown register read: $%04X\n", Address);
		    S9xMessage (S9X_TRACE, S9X_PPU_TRACE, String);
		}
#endif
		// XXX:
	        return (0); //Memory.FillRAM[Address]);
	    }
	}
	
	if (!Settings.SuperFX)
	    return (0x30);
#ifdef ZSNES_FX
	if (Address < 0x3040)
	    byte = S9xSuperFXReadReg (Address);
	else
	    byte = Memory.FillRAM [Address];

#ifdef CPU_SHUTDOWN
	if (Address == 0x3030)
	    CPU.WaitAddress = CPU.PCAtOpcodeStart;
#endif	
	if (Address == 0x3031)
	    CLEAR_IRQ_SOURCE (GSU_IRQ_SOURCE);
#else
	byte = Memory.FillRAM [Address];

//if (Address != 0x3030 && Address != 0x3031)
//printf ("%04x\n", Address);
#ifdef CPU_SHUTDOWN
	if (Address == 0x3030)
	{
	    CPU.WaitAddress = CPU.PCAtOpcodeStart;
	}
	else
#endif
	if (Address == 0x3031)
	{
	    CLEAR_IRQ_SOURCE (GSU_IRQ_SOURCE);
	    Memory.FillRAM [0x3031] = byte & 0x7f;
	}
	return (byte);
#endif
    }

    return (byte);
}

/**********************************************************************************************/
/* S9xSetCPU()                                                                                   */
/* This function sets a CPU/DMA Register to a specific byte                                   */
/**********************************************************************************************/
void S9xSetCPU (uint8 byte, uint16 Address)
{
    int d;
    
    if (Address < 0x4200)
    {
#ifdef VAR_CYCLES
	CPU.Cycles += ONE_CYCLE;
#endif
	switch (Address)
	{
	case 0x4016:
	    // S9xReset reading of old-style joypads
	    if ((byte & 1) && !(Memory.FillRAM [Address] & 1))
	    {
		PPU.Joypad1ButtonReadPos = 0;
		PPU.Joypad2ButtonReadPos = 0;
		PPU.Joypad3ButtonReadPos = 0;
	    }
	    break;
	case 0x4017:
	    break;
	default:
#ifdef DEBUGGER
	    missing.unknowncpu_write = Address;
	    if (Settings.TraceUnknownRegisters)
	    {
		sprintf (String, "Unknown register register write: $%02X->$%04X\n",
			 byte, Address);
		S9xMessage (S9X_TRACE, S9X_PPU_TRACE, String);
	    }
#endif
	    break;
	}
    }
    else
    switch (Address)
    {
    case 0x4200:
	// NMI, V & H IRQ and joypad reading enable flags
	if (byte & 0x20)
	{
	    if (!PPU.VTimerEnabled)
	    {
#ifdef DEBUGGER
		missing.virq = 1;
		missing.virq_pos = PPU.IRQVBeamPos;
#endif
		PPU.VTimerEnabled = TRUE;
		if (PPU.HTimerEnabled)
		    S9xUpdateHTimer ();
		else
		if (PPU.IRQVBeamPos == CPU.V_Counter)
		    S9xSetIRQ (PPU_V_BEAM_IRQ_SOURCE);
	    }
	}
	else
	    PPU.VTimerEnabled = FALSE;

	if (byte & 0x10)
	{
	    if (!PPU.HTimerEnabled)
	    {
#ifdef DEBUGGER
		missing.hirq = 1;
		missing.hirq_pos = PPU.IRQHBeamPos;
#endif
		PPU.HTimerEnabled = TRUE;
		S9xUpdateHTimer ();
	    }
	}
	else
	{
	    // No need to check for HTimer being disabled as the scanline
	    // event trigger code won't trigger an H-IRQ unless its enabled.
	    PPU.HTimerEnabled = FALSE;
	    PPU.HTimerPosition = Settings.H_Max + 1;
	}
	if (CPU.IRQCycleCount == 0)
	    CLEAR_IRQ_SOURCE (PPU_V_BEAM_IRQ_SOURCE | PPU_H_BEAM_IRQ_SOURCE);

	if ((byte & 0x80) && 
	    !(Memory.FillRAM [0x4200] & 0x80) &&
	    CPU.V_Counter >= PPU.ScreenHeight + FIRST_VISIBLE_LINE &&
	    CPU.V_Counter <= PPU.ScreenHeight + 15 &&
	    !CPU.NMIActive)
	{
	    CPU.Flags |= NMI_FLAG;
	    CPU.NMIActive = TRUE;
	    CPU.NMICycleCount = CPU.NMITriggerPoint;
	}
	break;
    case 0x4201:
	// I/O port output 
    case 0x4202:
	// Multiplier (for multply)
	break;
    case 0x4203:
	{
	    // Multiplicand
	    uint32 res = Memory.FillRAM[0x4202] * byte;

	    Memory.FillRAM[0x4216] = (uint8) res;
	    Memory.FillRAM[0x4217] = (uint8) (res >> 8);
	    break;
	}
    case 0x4204:
    case 0x4205:
	// Low and high muliplier (for divide)
	break;
    case 0x4206:
	{
	    // Divisor
	    uint16 a = Memory.FillRAM[0x4204] + (Memory.FillRAM[0x4205] << 8);
	    uint16 div = byte ? a / byte : 0xffff;
	    uint16 rem = byte ? a % byte : a;

	    Memory.FillRAM[0x4214] = (uint8)div;
	    Memory.FillRAM[0x4215] = div >> 8;
	    Memory.FillRAM[0x4216] = (uint8)rem;
	    Memory.FillRAM[0x4217] = rem >> 8;
	    break;
	}
    case 0x4207:
	d = PPU.IRQHBeamPos;
	PPU.IRQHBeamPos = (PPU.IRQHBeamPos & 0xFF00) | byte;

	if (PPU.HTimerEnabled && PPU.IRQHBeamPos != d)
	    S9xUpdateHTimer ();
	break;

    case 0x4208:
	d = PPU.IRQHBeamPos;
	PPU.IRQHBeamPos = (PPU.IRQHBeamPos & 0xFF) | ((byte & 1) << 8);

	if (PPU.HTimerEnabled && PPU.IRQHBeamPos != d)
	    S9xUpdateHTimer ();

	break;

    case 0x4209:
	d = PPU.IRQVBeamPos;
	PPU.IRQVBeamPos = (PPU.IRQVBeamPos & 0xFF00) | byte;
#ifdef DEBUGGER
	missing.virq_pos = PPU.IRQVBeamPos;
#endif
	if (PPU.VTimerEnabled && PPU.IRQVBeamPos != d)
	{
	    if (PPU.HTimerEnabled)
		S9xUpdateHTimer ();
	    else
	    {
		if (PPU.IRQVBeamPos == CPU.V_Counter)
		    S9xSetIRQ (PPU_V_BEAM_IRQ_SOURCE);
	    }
	}
	break;

    case 0x420A:
	d = PPU.IRQVBeamPos;
	PPU.IRQVBeamPos = (PPU.IRQVBeamPos & 0xFF) | ((byte & 1) << 8);
#ifdef DEBUGGER
	missing.virq_pos = PPU.IRQVBeamPos;
#endif
	if (PPU.VTimerEnabled && PPU.IRQVBeamPos != d)
	{
	    if (PPU.HTimerEnabled)
		S9xUpdateHTimer ();
	    else
	    {
		if (PPU.IRQVBeamPos == CPU.V_Counter)
		    S9xSetIRQ (PPU_V_BEAM_IRQ_SOURCE);
	    }
	}
	break;

    case 0x420B:
#ifdef DEBUGGER
	missing.dma_this_frame = byte;
	missing.dma_channels = byte;
#endif
	if ((byte & 0x01) != 0)
	    S9xDoDMA (0);
	if ((byte & 0x02) != 0)
	    S9xDoDMA (1);
	if ((byte & 0x04) != 0)
	    S9xDoDMA (2);
	if ((byte & 0x08) != 0)
	    S9xDoDMA (3);
	if ((byte & 0x10) != 0)
	    S9xDoDMA (4);
	if ((byte & 0x20) != 0)
	    S9xDoDMA (5);
	if ((byte & 0x40) != 0)
	    S9xDoDMA (6);
	if ((byte & 0x80) != 0)
	    S9xDoDMA (7);
	break;
    case 0x420C:
#ifdef DEBUGGER
	missing.hdma_this_frame |= byte;
	missing.hdma_channels |= byte; 
#endif
	if (Settings.DisableHDMA)
	    byte = 0;
	Memory.FillRAM[0x420c] = byte;
	IPPU.HDMA = byte;
	break;

    case 0x420d:
	// Cycle speed 0 - 2.68Mhz, 1 - 3.58Mhz (banks 0x80 +)
	if ((byte & 1) != (Memory.FillRAM [0x420d] & 1))
	{
	    if (byte & 1)
	    {
		CPU.FastROMSpeed = 6;
#ifdef DEBUGGER
		missing.fast_rom = 1;
#endif
	    }
	    else
		CPU.FastROMSpeed = 8;

	    Memory.FixROMSpeed ();
	}
	/* FALL */
    case 0x420e:
    case 0x420f:
	// --->>> Unknown
	break;
    case 0x4210:
	// NMI ocurred flag (reset on read or write)
	Memory.FillRAM[0x4210] = 0;
	return;
    case 0x4211:
	// IRQ ocurred flag (reset on read or write)
	CLEAR_IRQ_SOURCE (PPU_V_BEAM_IRQ_SOURCE | PPU_H_BEAM_IRQ_SOURCE);
	break;
    case 0x4212:
	// v-blank, h-blank and joypad being scanned flags (read-only)
    case 0x4213:
	// I/O Port (read-only)
    case 0x4214:
    case 0x4215:
	// Quotent of divide (read-only)
    case 0x4216:
    case 0x4217:
	// Multiply product (read-only)
	return;
    case 0x4218:
    case 0x4219:
    case 0x421a:
    case 0x421b:
    case 0x421c:
    case 0x421d: