path: root/src/cpuexec.cpp

/*
 * Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 *
 * (c) Copyright 1996 - 2001 Gary Henderson (gary.henderson@ntlworld.com) and
 *                           Jerremy Koot (jkoot@snes9x.com)
 *
 * Super FX C emulator code 
 * (c) Copyright 1997 - 1999 Ivar (ivar@snes9x.com) 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 (gary.henderson@ntlworld.com).
 *
 * DOS port code 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 "snes9x.h"

#include "memmap.h"
#include "cpuops.h"
#include "ppu.h"
#include "cpuexec.h"
#include "snapshot.h"
#include "gfx.h"
#include "missing.h"
#include "apu.h"
#include "dma.h"
#include "fxemu.h"
#ifdef USE_SA1
#include "sa1.h"
#endif

#include "os9x_asm_cpu.h"


void (*S9x_Current_HBlank_Event)();


#ifndef ASMCPU
	#ifdef USE_SA1
void S9xMainLoop_SA1_APU (void)
{
	for (;;)
    {
      asm_APU_EXECUTE(1);
      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 ();
		}
	    }

	  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
		CPU.IRQCycleCount--;
	    }
	  if (CPU.Flags & SCAN_KEYS_FLAG)
	    break;
	}

#ifdef CPU_SHUTDOWN
      CPU.PCAtOpcodeStart = CPU.PC;
#endif
#ifdef VAR_CYCLES
		CPU.Cycles += CPU.MemSpeed;
#else
		CPU.Cycles += ICPU.Speed [*CPU.PC];
#endif
      (*ICPU.S9xOpcodes[*CPU.PC++].S9xOpcode) ();


      //S9xUpdateAPUTimer ();


      if (SA1.Executing)
		S9xSA1MainLoop ();
      DO_HBLANK_CHECK ();

    }
}

void S9xMainLoop_SA1_NoAPU (void)
{
	for (;;)
    {
      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 ();
		}
	    }

	  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
		CPU.IRQCycleCount--;
	    }
	  if (CPU.Flags & SCAN_KEYS_FLAG)
	    break;
	}

#ifdef CPU_SHUTDOWN
      CPU.PCAtOpcodeStart = CPU.PC;
#endif
#ifdef VAR_CYCLES
		CPU.Cycles += CPU.MemSpeed;
#else
		CPU.Cycles += ICPU.Speed [*CPU.PC];
#endif
      (*ICPU.S9xOpcodes[*CPU.PC++].S9xOpcode) ();


      //S9xUpdateAPUTimer ();


      if (SA1.Executing)
		S9xSA1MainLoop ();
      DO_HBLANK_CHECK ();

    }
}
	// USE_SA1
	#endif

void S9xMainLoop_NoSA1_APU (void)
{
	for (;;)
    {
      asm_APU_EXECUTE(1);
      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 ();
		}
	    }

	  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
		CPU.IRQCycleCount--;
	    }
	  if (CPU.Flags & SCAN_KEYS_FLAG)
	    break;
	}

#ifdef CPU_SHUTDOWN
      CPU.PCAtOpcodeStart = CPU.PC;
#endif
#ifdef VAR_CYCLES
		CPU.Cycles += CPU.MemSpeed;
#else
		CPU.Cycles += ICPU.Speed [*CPU.PC];
#endif
      (*ICPU.S9xOpcodes[*CPU.PC++].S9xOpcode) ();


      //S9xUpdateAPUTimer ();

      DO_HBLANK_CHECK ();
    }
}

void S9xMainLoop_NoSA1_NoAPU (void)
{
	for (;;)
    {
      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 ();
		}
	    }

	  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
		CPU.IRQCycleCount--;
	    }
	  if (CPU.Flags & SCAN_KEYS_FLAG)
	    break;
	}

#ifdef CPU_SHUTDOWN
      CPU.PCAtOpcodeStart = CPU.PC;
#endif
#ifdef VAR_CYCLES
		CPU.Cycles += CPU.MemSpeed;
#else
		CPU.Cycles += ICPU.Speed [*CPU.PC];
#endif
      (*ICPU.S9xOpcodes[*CPU.PC++].S9xOpcode) ();


      //S9xUpdateAPUTimer ();


      DO_HBLANK_CHECK ();

    }
}
#endif 


void
S9xMainLoop (void)
{
#ifndef ASMCPU
	if (Settings.APUEnabled == 1) {
	#ifdef USE_SA1
		if (Settings.SA1) S9xMainLoop_SA1_APU();
		else
	#endif 
		  S9xMainLoop_NoSA1_APU();
	} else {
	#ifdef USE_SA1
		if (Settings.SA1) S9xMainLoop_SA1_NoAPU();
		else S9xMainLoop_NoSA1_NoAPU();
	#endif 

	}
#else  
  if (Settings.asmspc700) asmMainLoop_spcAsm(&CPU);
  else asmMainLoop_spcC(&CPU);		
#endif
  Registers.PC = CPU.PC - CPU.PCBase;

#ifndef ASMCPU
  S9xPackStatus ();
#endif

  S9xAPUPackStatus ();


  //if (CPU.Flags & SCAN_KEYS_FLAG)
   // {
      CPU.Flags &= ~SCAN_KEYS_FLAG;
    //}
    
    if (CPU.BRKTriggered && Settings.SuperFX && !CPU.TriedInterleavedMode2)
    {
	CPU.TriedInterleavedMode2 = TRUE;
	CPU.BRKTriggered = FALSE;
	S9xDeinterleaveMode2 ();
    }
}

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);
}

void S9xDoHBlankProcessing ()
{
#ifdef CPU_SHUTDOWN
    CPU.WaitCounter++;
#endif

    switch (CPU.WhichEvent)
    {
    case HBLANK_START_EVENT:
		if (IPPU.HDMA && CPU.V_Counter <= PPU.ScreenHeight)
			IPPU.HDMA = S9xDoHDMA (IPPU.HDMA);
		break;

    case HBLANK_END_EVENT:
		asm_APU_EXECUTE(3); // notaz: run spc700 in sound 'speed hack' mode
		if(Settings.SuperFX)
			S9xSuperFXExec ();

		CPU.Cycles -= Settings.H_Max;
		if (/*IAPU.APUExecuting*/CPU.APU_APUExecuting)
			CPU.APU_Cycles -= Settings.H_Max;
		else
			CPU.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;
			CPU.NMIActive = FALSE;
			ICPU.Frame++;
			PPU.HVBeamCounterLatched = 0;
			CPU.Flags |= SCAN_KEYS_FLAG;
			S9xStartHDMA ();
		}

		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;
			PPU.OAMFlip = 0;
			PPU.FirstSprite = 0;
			if(PPU.OAMPriorityRotation)
				PPU.FirstSprite = PPU.OAMAddr>>1;
		}

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

			}

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

		if (CPU.V_Counter == FIRST_VISIBLE_LINE)
		{
			Memory.FillRAM[0x4210] = 0;
			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*/CPU.APU_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*/CPU.APU_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*/CPU.APU_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 ();
}