path: root/source/cpuexec.cpp

/*******************************************************************************
  Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 
  (c) Copyright 1996 - 2002 Gary Henderson (gary.henderson@ntlworld.com) and
                            Jerremy Koot (jkoot@snes9x.com)

  (c) Copyright 2001 - 2004 John Weidman (jweidman@slip.net)

  (c) Copyright 2002 - 2004 Brad Jorsch (anomie@users.sourceforge.net),
                            funkyass (funkyass@spam.shaw.ca),
                            Joel Yliluoma (http://iki.fi/bisqwit/)
                            Kris Bleakley (codeviolation@hotmail.com),
                            Matthew Kendora,
                            Nach (n-a-c-h@users.sourceforge.net),
                            Peter Bortas (peter@bortas.org) and
                            zones (kasumitokoduck@yahoo.com)

  C4 x86 assembler and some C emulation code
  (c) Copyright 2000 - 2003 zsKnight (zsknight@zsnes.com),
                            _Demo_ (_demo_@zsnes.com), and Nach

  C4 C++ code
  (c) Copyright 2003 Brad Jorsch

  DSP-1 emulator code
  (c) Copyright 1998 - 2004 Ivar (ivar@snes9x.com), _Demo_, Gary Henderson,
                            John Weidman, neviksti (neviksti@hotmail.com),
                            Kris Bleakley, Andreas Naive

  DSP-2 emulator code
  (c) Copyright 2003 Kris Bleakley, John Weidman, neviksti, Matthew Kendora, and
                     Lord Nightmare (lord_nightmare@users.sourceforge.net

  OBC1 emulator code
  (c) Copyright 2001 - 2004 zsKnight, pagefault (pagefault@zsnes.com) and
                            Kris Bleakley
  Ported from x86 assembler to C by sanmaiwashi

  SPC7110 and RTC C++ emulator code
  (c) Copyright 2002 Matthew Kendora with research by
                     zsKnight, John Weidman, and Dark Force

  S-DD1 C emulator code
  (c) Copyright 2003 Brad Jorsch with research by
                     Andreas Naive and John Weidman
 
  S-RTC C emulator code
  (c) Copyright 2001 John Weidman
  
  ST010 C++ emulator code
  (c) Copyright 2003 Feather, Kris Bleakley, John Weidman and Matthew Kendora

  Super FX x86 assembler emulator code 
  (c) Copyright 1998 - 2003 zsKnight, _Demo_, and pagefault 

  Super FX C emulator code 
  (c) Copyright 1997 - 1999 Ivar, Gary Henderson and John Weidman


  SH assembler code partly based on x86 assembler code
  (c) Copyright 2002 - 2004 Marcus Comstedt (marcus@mc.pp.se) 

 
  Specific ports contains the works of other authors. See headers in
  individual files.
 
  Snes9x homepage: http://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 "ds2_timer.h"
#include "ds2_cpu.h"
#include "ds2io.h"

#include "snes9x.h"
#include "memmap.h"
#include "cpuops.h"
#include "ppu.h"
#include "cpuexec.h"
#include "debug.h"
#include "snapshot.h"
#include "gfx.h"
#include "missing.h"
#include "apu.h"
#include "dma.h"
#include "fxemu.h"
#include "sa1.h"
#include "spc7110.h"

#ifdef ACCUMULATE_JOYPAD
#include "display.h"
#endif

extern void S9xProcessSound (unsigned int);

void S9xMainLoop_SA1_SFX     (void);
void S9xMainLoop_SA1_NoSFX   (void);
void S9xMainLoop_NoSA1_SFX   (void);
void S9xMainLoop_NoSA1_NoSFX (void);

/*
 * This is a CATSFC modification inspired by a Snes9x-Euphoria modification.
 * The emulator selects a main loop based on the chips used in an entire
 * frame. This avoids the constant SA1.Executing and Settings.SuperFX checks.
 *
 * The original version of S9xMainLoop is S9xMainLoop_SA1_SFX below. Remember
 * to propagate modifications to the SA1_NoSFX, NoSA1_SFX and NoSA1_NoSFX
 * versions.
 */
void S9xMainLoop (void)
{
	if (Settings.SA1)
	{
		if (Settings.SuperFX)             S9xMainLoop_SA1_SFX   ();
		else /* if (!Settings.SuperFX) */ S9xMainLoop_SA1_NoSFX ();
	}
	else /* if (!Settings.SA1) */
	{
		if (Settings.SuperFX)             S9xMainLoop_NoSA1_SFX   ();
		else /* if (!Settings.SuperFX) */ S9xMainLoop_NoSA1_NoSFX ();
	}
}

void S9xMainLoop_SA1_SFX (void)
{
    for (;;)
	{
    	APU_EXECUTE ();
    
    	if (CPU.Flags)
    	{
    	    if (CPU.Flags & NMI_FLAG)
    	    {
        		if (--CPU.NMICycleCount == 0) {
        		    CPU.Flags &= ~NMI_FLAG;
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    S9xOpcode_NMI ();
        		}
    	    }

    	    CHECK_SOUND ();

    	    if (CPU.Flags & IRQ_PENDING_FLAG)
    	    {
        		if (CPU.IRQCycleCount == 0)
        		{
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    if (CPU.IRQActive && !Settings.DisableIRQ) {
            			if (!CheckFlag (IRQ))
            			    S9xOpcode_IRQ ();
        		    }
        		    else
            			CPU.Flags &= ~IRQ_PENDING_FLAG;
        		}
        		else
                {
                    if(--CPU.IRQCycleCount==0 && CheckFlag (IRQ))
                        CPU.IRQCycleCount=1;
                }
    	    }

    	    if (CPU.Flags & SCAN_KEYS_FLAG)
	        	break;
    	}

#ifdef CPU_SHUTDOWN
    	CPU.PCAtOpcodeStart = CPU.PC;
#endif
    	CPU.Cycles += CPU.MemSpeed;

    	(*ICPU.S9xOpcodes [*CPU.PC++].S9xOpcode) ();
	
    	if (SA1.Executing)
    	    S9xSA1MainLoop ();
    	DO_HBLANK_CHECK_SFX();
    }

    ICPU.Registers.PC = CPU.PC - CPU.PCBase;
    S9xPackStatus ();
    IAPU.Registers.PC = IAPU.PC - IAPU.RAM;
    S9xAPUPackStatus ();
    if (CPU.Flags & SCAN_KEYS_FLAG)
    {
	    S9xSyncSpeed ();
        CPU.Flags &= ~SCAN_KEYS_FLAG;
    }

#ifdef DETECT_NASTY_FX_INTERLEAVE
    if (CPU.BRKTriggered && Settings.SuperFX && !CPU.TriedInterleavedMode2)
    {
    	CPU.TriedInterleavedMode2 = TRUE;
    	CPU.BRKTriggered = FALSE;
    	S9xDeinterleaveMode2 ();
    }
#endif
}

void S9xMainLoop_SA1_NoSFX (void)
{
    for (;;)
	{
    	APU_EXECUTE ();
    
    	if (CPU.Flags)
    	{
    	    if (CPU.Flags & NMI_FLAG)
    	    {
        		if (--CPU.NMICycleCount == 0) {
        		    CPU.Flags &= ~NMI_FLAG;
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    S9xOpcode_NMI ();
        		}
    	    }

    	    CHECK_SOUND ();

    	    if (CPU.Flags & IRQ_PENDING_FLAG)
    	    {
        		if (CPU.IRQCycleCount == 0)
        		{
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    if (CPU.IRQActive && !Settings.DisableIRQ) {
            			if (!CheckFlag (IRQ))
            			    S9xOpcode_IRQ ();
        		    }
        		    else
            			CPU.Flags &= ~IRQ_PENDING_FLAG;
        		}
        		else
                {
                    if(--CPU.IRQCycleCount==0 && CheckFlag (IRQ))
                        CPU.IRQCycleCount=1;
                }
    	    }

    	    if (CPU.Flags & SCAN_KEYS_FLAG)
	        	break;
    	}

#ifdef CPU_SHUTDOWN
    	CPU.PCAtOpcodeStart = CPU.PC;
#endif
    	CPU.Cycles += CPU.MemSpeed;

    	(*ICPU.S9xOpcodes [*CPU.PC++].S9xOpcode) ();
	
    	if (SA1.Executing)
    	    S9xSA1MainLoop ();
    	DO_HBLANK_CHECK_NoSFX();
    }

    ICPU.Registers.PC = CPU.PC - CPU.PCBase;
    S9xPackStatus ();
    IAPU.Registers.PC = IAPU.PC - IAPU.RAM;
    S9xAPUPackStatus ();
    if (CPU.Flags & SCAN_KEYS_FLAG)
    {
	    S9xSyncSpeed ();
        CPU.Flags &= ~SCAN_KEYS_FLAG;
    }
}

void S9xMainLoop_NoSA1_SFX (void)
{
    for (;;)
	{
    	APU_EXECUTE ();
    
    	if (CPU.Flags)
    	{
    	    if (CPU.Flags & NMI_FLAG)
    	    {
        		if (--CPU.NMICycleCount == 0) {
        		    CPU.Flags &= ~NMI_FLAG;
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    S9xOpcode_NMI ();
        		}
    	    }

    	    CHECK_SOUND ();

    	    if (CPU.Flags & IRQ_PENDING_FLAG)
    	    {
        		if (CPU.IRQCycleCount == 0)
        		{
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    if (CPU.IRQActive && !Settings.DisableIRQ) {
            			if (!CheckFlag (IRQ))
            			    S9xOpcode_IRQ ();
        		    }
        		    else
            			CPU.Flags &= ~IRQ_PENDING_FLAG;
        		}
        		else
                {
                    if(--CPU.IRQCycleCount==0 && CheckFlag (IRQ))
                        CPU.IRQCycleCount=1;
                }
    	    }

    	    if (CPU.Flags & SCAN_KEYS_FLAG)
	        	break;
    	}

#ifdef CPU_SHUTDOWN
    	CPU.PCAtOpcodeStart = CPU.PC;
#endif
    	CPU.Cycles += CPU.MemSpeed;

    	(*ICPU.S9xOpcodes [*CPU.PC++].S9xOpcode) ();
	
    	DO_HBLANK_CHECK_SFX();
    }

    ICPU.Registers.PC = CPU.PC - CPU.PCBase;
    S9xPackStatus ();
    IAPU.Registers.PC = IAPU.PC - IAPU.RAM;
    S9xAPUPackStatus ();
    if (CPU.Flags & SCAN_KEYS_FLAG)
    {
	    S9xSyncSpeed ();
        CPU.Flags &= ~SCAN_KEYS_FLAG;
    }

#ifdef DETECT_NASTY_FX_INTERLEAVE
    if (CPU.BRKTriggered && Settings.SuperFX && !CPU.TriedInterleavedMode2)
    {
    	CPU.TriedInterleavedMode2 = TRUE;
    	CPU.BRKTriggered = FALSE;
    	S9xDeinterleaveMode2 ();
    }
#endif
}

void S9xMainLoop_NoSA1_NoSFX (void)
{
    for (;;)
	{
    	APU_EXECUTE ();
    
    	if (CPU.Flags)
    	{
    	    if (CPU.Flags & NMI_FLAG)
    	    {
        		if (--CPU.NMICycleCount == 0) {
        		    CPU.Flags &= ~NMI_FLAG;
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    S9xOpcode_NMI ();
        		}
    	    }

    	    CHECK_SOUND ();

    	    if (CPU.Flags & IRQ_PENDING_FLAG)
    	    {
        		if (CPU.IRQCycleCount == 0)
        		{
        		    if (CPU.WaitingForInterrupt) {
            			CPU.WaitingForInterrupt = FALSE;
            			CPU.PC++;
        		    }
        		    if (CPU.IRQActive && !Settings.DisableIRQ) {
            			if (!CheckFlag (IRQ))
            			    S9xOpcode_IRQ ();
        		    }
        		    else
            			CPU.Flags &= ~IRQ_PENDING_FLAG;
        		}
        		else
                {
                    if(--CPU.IRQCycleCount==0 && CheckFlag (IRQ))
                        CPU.IRQCycleCount=1;
                }
    	    }

    	    if (CPU.Flags & SCAN_KEYS_FLAG)
	        	break;
    	}

#ifdef CPU_SHUTDOWN
    	CPU.PCAtOpcodeStart = CPU.PC;
#endif
    	CPU.Cycles += CPU.MemSpeed;

    	(*ICPU.S9xOpcodes [*CPU.PC++].S9xOpcode) ();
	
    	DO_HBLANK_CHECK_NoSFX();
    }

    ICPU.Registers.PC = CPU.PC - CPU.PCBase;
    S9xPackStatus ();
    IAPU.Registers.PC = IAPU.PC - IAPU.RAM;
    S9xAPUPackStatus ();
    if (CPU.Flags & SCAN_KEYS_FLAG)
    {
	    S9xSyncSpeed ();
        CPU.Flags &= ~SCAN_KEYS_FLAG;
    }
}

void S9xSetIRQ (uint32 source)
{
    CPU.IRQActive |= source;
    CPU.Flags |= IRQ_PENDING_FLAG;
    CPU.IRQCycleCount = 3;
    if (CPU.WaitingForInterrupt)
    {
	// Force IRQ to trigger immediately after WAI - 
	// Final Fantasy Mystic Quest crashes without this.
	CPU.IRQCycleCount = 0;
	CPU.WaitingForInterrupt = FALSE;
	CPU.PC++;
    }
}

void S9xClearIRQ (uint32 source)
{
    CLEAR_IRQ_SOURCE (source);
}

/*
 * This is a CATSFC modification inspired by a Snes9x-Euphoria modification.
 * The emulator selects an HBlank processor based on the chips used in an
 * entire frame. This avoids the constant Settings.SuperFX checks.
 *
 * The original version of S9xDoHBlankProcessing is S9xDoHBlankProcessing_SFX
 * below. Remember to propagate modifications to the NoSFX version.
 */
void S9xDoHBlankProcessing_SFX ()
{
#ifdef CPU_SHUTDOWN
    CPU.WaitCounter++;
#endif
    switch (CPU.WhichEvent)
    {
		case HBLANK_START_EVENT:
#ifdef ACCUMULATE_JOYPAD
/*
 * This call allows NDSSFC to synchronise the DS controller more often.
 * If porting a later version of Snes9x into NDSSFC, it is essential to
 * preserve it.
 */
		if ((CPU.V_Counter & 0xF) == 0)
			NDSSFCAccumulateJoypad ();
#endif
		if (IPPU.HDMA && CPU.V_Counter <= PPU.ScreenHeight)
			IPPU.HDMA = S9xDoHDMA (IPPU.HDMA);

		break;

		case HBLANK_END_EVENT:
		S9xSuperFXExec ();

#ifndef STORM
		if (Settings.SoundSync)
			S9xGenerateSound ();
#endif

		CPU.Cycles -= Settings.H_Max;
		if (IAPU.APUExecuting)
		{
			APU.Cycles -= Settings.H_Max;
#ifdef MK_APU
			S9xCatchupCount();
#endif
		}
		else
			APU.Cycles = 0;

		CPU.NextEvent = -1;
		ICPU.Scanline++;

		if (++CPU.V_Counter >= (Settings.PAL ? SNES_MAX_PAL_VCOUNTER : SNES_MAX_NTSC_VCOUNTER))
		{
			CPU.V_Counter = 0;
			Memory.FillRAM[0x213F]^=0x80;
			PPU.RangeTimeOver = 0;
			CPU.NMIActive = FALSE;
			ICPU.Frame++;
			PPU.HVBeamCounterLatched = 0;
			CPU.Flags |= SCAN_KEYS_FLAG;
			S9xStartHDMA ();
		}

		S9xProcessSound (0);

		if (PPU.VTimerEnabled && !PPU.HTimerEnabled && CPU.V_Counter == PPU.IRQVBeamPos)
		{
			S9xSetIRQ (PPU_V_BEAM_IRQ_SOURCE);
		}

		if (CPU.V_Counter == PPU.ScreenHeight + FIRST_VISIBLE_LINE)
		{
			// Start of V-blank
			S9xEndScreenRefresh ();
			IPPU.HDMA = 0;
		    // Bits 7 and 6 of $4212 are computed when read in S9xGetPPU.
		    missing.dma_this_frame = 0;
		    IPPU.MaxBrightness = PPU.Brightness;
		    PPU.ForcedBlanking = (Memory.FillRAM [0x2100] >> 7) & 1;

			if(!PPU.ForcedBlanking)
			{
				PPU.OAMAddr = PPU.SavedOAMAddr;

				uint8 tmp = 0;
				if(PPU.OAMPriorityRotation)
					tmp = (PPU.OAMAddr&0xFE)>>1;
				if((PPU.OAMFlip&1) || PPU.FirstSprite!=tmp)
				{
					PPU.FirstSprite=tmp;
					IPPU.OBJChanged=TRUE;
				}

				PPU.OAMFlip = 0;
			}

			Memory.FillRAM[0x4210] = 0x80 |Model->_5A22;
		    if (Memory.FillRAM[0x4200] & 0x80)
		    {
				CPU.NMIActive = TRUE;
				CPU.Flags |= NMI_FLAG;
				CPU.NMICycleCount = CPU.NMITriggerPoint;
		    }

#ifdef OLD_SNAPSHOT_CODE
		    if (CPU.Flags & SAVE_SNAPSHOT_FLAG)
			{
				CPU.Flags &= ~SAVE_SNAPSHOT_FLAG;
				Registers.PC = CPU.PC - CPU.PCBase;
				S9xPackStatus ();
				S9xAPUPackStatus ();
				Snapshot (NULL);
			}
#endif
		}

		if (CPU.V_Counter == PPU.ScreenHeight + 3)
			S9xUpdateJoypads ();

		if (CPU.V_Counter == FIRST_VISIBLE_LINE)
		{
			Memory.FillRAM[0x4210] = Model->_5A22;
			CPU.Flags &= ~NMI_FLAG;
			S9xStartScreenRefresh ();
		}
		if (CPU.V_Counter >= FIRST_VISIBLE_LINE &&
			CPU.V_Counter < PPU.ScreenHeight + FIRST_VISIBLE_LINE)
		{
			RenderLine (CPU.V_Counter - FIRST_VISIBLE_LINE);
		}
	// Use TimerErrorCounter to skip update of SPC700 timers once
	// every 128 updates. Needed because this section of code is called
	// once every emulated 63.5 microseconds, which coresponds to
	// 15.750KHz, but the SPC700 timers need to be updated at multiples
	// of 8KHz, hence the error correction.
//	IAPU.TimerErrorCounter++;
//	if (IAPU.TimerErrorCounter >= )
//	    IAPU.TimerErrorCounter = 0;
//	else
	{
		if (APU.TimerEnabled [2])
		{
			APU.Timer [2] += 4;
			while (APU.Timer [2] >= APU.TimerTarget [2])
			{
				IAPU.RAM [0xff] = (IAPU.RAM [0xff] + 1) & 0xf;
				APU.Timer [2] -= APU.TimerTarget [2];
#ifdef SPC700_SHUTDOWN		
				IAPU.WaitCounter++;
				IAPU.APUExecuting = TRUE;
#endif
			}
		}
		if (CPU.V_Counter & 1)
		{
			if (APU.TimerEnabled [0])
			{
				APU.Timer [0]++;
				if (APU.Timer [0] >= APU.TimerTarget [0])
				{
					IAPU.RAM [0xfd] = (IAPU.RAM [0xfd] + 1) & 0xf;
					APU.Timer [0] = 0;
#ifdef SPC700_SHUTDOWN		
					IAPU.WaitCounter++;
					IAPU.APUExecuting = TRUE;
#endif
				}
			}
			if (APU.TimerEnabled [1])
			{
				APU.Timer [1]++;
				if (APU.Timer [1] >= APU.TimerTarget [1])
				{
					IAPU.RAM [0xfe] = (IAPU.RAM [0xfe] + 1) & 0xf;
					APU.Timer [1] = 0;
#ifdef SPC700_SHUTDOWN		
					IAPU.WaitCounter++;
					IAPU.APUExecuting = TRUE;
#endif		    
				}
			}
	    }
	}
		break;

	    case HTIMER_BEFORE_EVENT:
	    case HTIMER_AFTER_EVENT:
		if (PPU.HTimerEnabled && (!PPU.VTimerEnabled || CPU.V_Counter == PPU.IRQVBeamPos))
		{
		    S9xSetIRQ (PPU_H_BEAM_IRQ_SOURCE);
		}
		break;
	}

    S9xReschedule ();
}
void S9xDoHBlankProcessing_NoSFX ()
{
#ifdef CPU_SHUTDOWN
    CPU.WaitCounter++;
#endif
    switch (CPU.WhichEvent)
    {
		case HBLANK_START_EVENT:
#ifdef ACCUMULATE_JOYPAD
/*
 * This call allows NDSSFC to synchronise the DS controller more often.
 * If porting a later version of Snes9x into NDSSFC, it is essential to
 * preserve it.
 */
		NDSSFCAccumulateJoypad ();
#endif
		if (IPPU.HDMA && CPU.V_Counter <= PPU.ScreenHeight)
			IPPU.HDMA = S9xDoHDMA (IPPU.HDMA);

		break;

		case HBLANK_END_EVENT:

#ifndef STORM
		if (Settings.SoundSync)
			S9xGenerateSound ();
#endif

		CPU.Cycles -= Settings.H_Max;
		if (IAPU.APUExecuting)
		{
			APU.Cycles -= Settings.H_Max;
#ifdef MK_APU
			S9xCatchupCount();
#endif
		}
		else
			APU.Cycles = 0;

		CPU.NextEvent = -1;
		ICPU.Scanline++;

		if (++CPU.V_Counter >= (Settings.PAL ? SNES_MAX_PAL_VCOUNTER : SNES_MAX_NTSC_VCOUNTER))
		{
			CPU.V_Counter = 0;
			Memory.FillRAM[0x213F]^=0x80;
			PPU.RangeTimeOver = 0;
			CPU.NMIActive = FALSE;
			ICPU.Frame++;
			PPU.HVBeamCounterLatched = 0;
			CPU.Flags |= SCAN_KEYS_FLAG;
			S9xStartHDMA ();
		}

		S9xProcessSound (0);

		if (PPU.VTimerEnabled && !PPU.HTimerEnabled && CPU.V_Counter == PPU.IRQVBeamPos)
		{
			S9xSetIRQ (PPU_V_BEAM_IRQ_SOURCE);
		}

		if (CPU.V_Counter == PPU.ScreenHeight + FIRST_VISIBLE_LINE)
		{
			// Start of V-blank
			S9xEndScreenRefresh ();
			IPPU.HDMA = 0;
		    // Bits 7 and 6 of $4212 are computed when read in S9xGetPPU.
		    missing.dma_this_frame = 0;
		    IPPU.MaxBrightness = PPU.Brightness;
		    PPU.ForcedBlanking = (Memory.FillRAM [0x2100] >> 7) & 1;

			if(!PPU.ForcedBlanking)
			{
				PPU.OAMAddr = PPU.SavedOAMAddr;

				uint8 tmp = 0;
				if(PPU.OAMPriorityRotation)
					tmp = (PPU.OAMAddr&0xFE)>>1;
				if((PPU.OAMFlip&1) || PPU.FirstSprite!=tmp)
				{
					PPU.FirstSprite=tmp;
					IPPU.OBJChanged=TRUE;
				}

				PPU.OAMFlip = 0;
			}

			Memory.FillRAM[0x4210] = 0x80 |Model->_5A22;
		    if (Memory.FillRAM[0x4200] & 0x80)
		    {
				CPU.NMIActive = TRUE;
				CPU.Flags |= NMI_FLAG;
				CPU.NMICycleCount = CPU.NMITriggerPoint;
		    }

#ifdef OLD_SNAPSHOT_CODE
		    if (CPU.Flags & SAVE_SNAPSHOT_FLAG)
			{
				CPU.Flags &= ~SAVE_SNAPSHOT_FLAG;
				Registers.PC = CPU.PC - CPU.PCBase;
				S9xPackStatus ();
				S9xAPUPackStatus ();
				Snapshot (NULL);
			}
#endif
		}

		if (CPU.V_Counter == PPU.ScreenHeight + 3)
			S9xUpdateJoypads ();

		if (CPU.V_Counter == FIRST_VISIBLE_LINE)
		{
			Memory.FillRAM[0x4210] = Model->_5A22;
			CPU.Flags &= ~NMI_FLAG;
			S9xStartScreenRefresh ();
		}
		if (CPU.V_Counter >= FIRST_VISIBLE_LINE &&
			CPU.V_Counter < PPU.ScreenHeight + FIRST_VISIBLE_LINE)
		{
			RenderLine (CPU.V_Counter - FIRST_VISIBLE_LINE);
		}
	// Use TimerErrorCounter to skip update of SPC700 timers once
	// every 128 updates. Needed because this section of code is called
	// once every emulated 63.5 microseconds, which coresponds to
	// 15.750KHz, but the SPC700 timers need to be updated at multiples
	// of 8KHz, hence the error correction.
//	IAPU.TimerErrorCounter++;
//	if (IAPU.TimerErrorCounter >= )
//	    IAPU.TimerErrorCounter = 0;
//	else
	{
		if (APU.TimerEnabled [2])
		{
			APU.Timer [2] += 4;
			while (APU.Timer [2] >= APU.TimerTarget [2])
			{
				IAPU.RAM [0xff] = (IAPU.RAM [0xff] + 1) & 0xf;
				APU.Timer [2] -= APU.TimerTarget [2];
#ifdef SPC700_SHUTDOWN		
				IAPU.WaitCounter++;
				IAPU.APUExecuting = TRUE;
#endif
			}
		}
		if (CPU.V_Counter & 1)
		{
			if (APU.TimerEnabled [0])
			{
				APU.Timer [0]++;
				if (APU.Timer [0] >= APU.TimerTarget [0])
				{
					IAPU.RAM [0xfd] = (IAPU.RAM [0xfd] + 1) & 0xf;
					APU.Timer [0] = 0;
#ifdef SPC700_SHUTDOWN		
					IAPU.WaitCounter++;
					IAPU.APUExecuting = TRUE;
#endif
				}
			}
			if (APU.TimerEnabled [1])
			{
				APU.Timer [1]++;
				if (APU.Timer [1] >= APU.TimerTarget [1])
				{
					IAPU.RAM [0xfe] = (IAPU.RAM [0xfe] + 1) & 0xf;
					APU.Timer [1] = 0;
#ifdef SPC700_SHUTDOWN		
					IAPU.WaitCounter++;
					IAPU.APUExecuting = TRUE;
#endif		    
				}
			}
	    }
	}
		break;

	    case HTIMER_BEFORE_EVENT:
	    case HTIMER_AFTER_EVENT:
		if (PPU.HTimerEnabled && (!PPU.VTimerEnabled || CPU.V_Counter == PPU.IRQVBeamPos))
		{
		    S9xSetIRQ (PPU_H_BEAM_IRQ_SOURCE);
		}
		break;
	}

    S9xReschedule ();
}