apu.cpp

著名SFC模拟器Snes9x的源代码。

/*
 * Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 *
 * (c) Copyright 1996 - 2001 Gary Henderson ([e-mail]) and
 *                           Jerremy Koot ([e-mail])
 *
 * Super FX C emulator code 
 * (c) Copyright 1997 - 1999 Ivar ([e-mail]) 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 ([e-mail]).
 *
 * DOS port code contains the works of other authors. See headers in
 * individual files.
 *
 * Snes9x homepage: 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.
 */
#ifdef __DJGPP
#include <allegro.h>
#undef TRUE
#endif

#include "snes9x.h"
#include "spc700.h"
#include "apu.h"
#include "soundux.h"
#include "cpuexec.h"

extern int NoiseFreq [32];
#ifdef DEBUGGER
void S9xTraceSoundDSP (const char *s, int i1 = 0, int i2 = 0, int i3 = 0,
		       int i4 = 0, int i5 = 0, int i6 = 0, int i7 = 0);
#endif

bool8 S9xInitAPU ()
{
    IAPU.RAM = new uint8 [0x10000];
    IAPU.ShadowRAM = new uint8 [0x10000];
    IAPU.CachedSamples = new uint8 [0x40000];
    
    if (!IAPU.RAM || !IAPU.ShadowRAM || !IAPU.CachedSamples)
	return (FALSE);

    return (TRUE);
}

void S9xDeinitAPU ()
{
    delete IAPU.RAM;
    delete IAPU.ShadowRAM;
    delete IAPU.CachedSamples;
}

EXTERN_C uint8 APUROM [64];

void S9xResetAPU ()
{
    Settings.APUEnabled = Settings.NextAPUEnabled;

    memset (IAPU.RAM, 0xff, 0x10000);
    
    ZeroMemory (IAPU.ShadowRAM, 0x10000);
    ZeroMemory (IAPU.CachedSamples, 0x40000);
    ZeroMemory (APU.OutPorts, 4);
    IAPU.DirectPage = IAPU.RAM;
    memmove (&IAPU.RAM [0xffc0], APUROM, sizeof (APUROM));
    memmove (APU.ExtraRAM, APUROM, sizeof (APUROM));
    IAPU.PC = IAPU.RAM + IAPU.RAM [0xfffe] + (IAPU.RAM [0xffff] << 8);
    APU.Cycles = 0;
    APURegisters.YA.W = 0;
    APURegisters.X = 0;
    APURegisters.S = 0xff;
    APURegisters.P = 0;
    S9xAPUUnpackStatus ();
    APURegisters.PC = 0;
    IAPU.APUExecuting = Settings.APUEnabled;
#ifdef SPC700_SHUTDOWN
    IAPU.WaitAddress1 = NULL;
    IAPU.WaitAddress2 = NULL;
    IAPU.WaitCounter = 0;
#endif
    APU.ShowROM = TRUE;
    IAPU.RAM [0xf1] = 0x80;

    int i;

    for (i = 0; i < 3; i++)
    {
	APU.TimerEnabled [i] = FALSE;
	APU.TimerValueWritten [i] = 0;
	APU.TimerTarget [i] = 0;
	APU.Timer [i] = 0;
    }
    for (int j = 0; j < 0x80; j++)
	APU.DSP [j] = 0;

    IAPU.TwoCycles = IAPU.OneCycle * 2;

    for (i = 0; i < 256; i++)
	S9xAPUCycles [i] = S9xAPUCycleLengths [i] * IAPU.OneCycle;

    APU.DSP [APU_ENDX] = 0;
    APU.DSP [APU_KOFF] = 0;
    APU.DSP [APU_KON] = 0;
    APU.DSP [APU_FLG] = APU_MUTE | APU_ECHO_DISABLED;
    APU.KeyedChannels = 0;

    S9xResetSound (TRUE);
    S9xSetEchoEnable (0);
}

void S9xSetAPUDSP (uint8 byte)
{
    uint8 reg = IAPU.RAM [0xf2];
    int i;

    switch (reg)
    {
    case APU_FLG:
	if (byte & APU_SOFT_RESET)
	{
	    APU.DSP [reg] = APU_MUTE | APU_ECHO_DISABLED | (byte & 0x1f);
	    APU.DSP [APU_ENDX] = 0;
	    APU.DSP [APU_KOFF] = 0;
	    APU.DSP [APU_KON] = 0;
	    S9xSetEchoWriteEnable (FALSE);
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] DSP reset\n", ICPU.Scanline);
#endif
	    // Kill sound
	    S9xResetSound (FALSE);
	}
	else
	{
	    S9xSetEchoWriteEnable (!(byte & APU_ECHO_DISABLED));
	    if (byte & APU_MUTE)
	    {
#ifdef DEBUGGER
		if (Settings.TraceSoundDSP)
		    S9xTraceSoundDSP ("[%d] Mute sound\n", ICPU.Scanline);
#endif
		S9xSetSoundMute (TRUE);
	    }
	    else
		S9xSetSoundMute (FALSE);

	    SoundData.noise_hertz = NoiseFreq [byte & 0x1f];
	    for (i = 0; i < 8; i++)
	    {
		if (SoundData.channels [i].type == SOUND_NOISE)
		    S9xSetSoundFrequency (i, SoundData.noise_hertz);
	    }
	}
	break;
    case APU_NON:
	if (byte != APU.DSP [APU_NON])
	{
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] Noise:", ICPU.Scanline);
#endif
	    uint8 mask = 1;
	    for (int c = 0; c < 8; c++, mask <<= 1)
	    {
		int type;
		if (byte & mask)
		{
		    type = SOUND_NOISE;
#ifdef DEBUGGER
		    if (Settings.TraceSoundDSP)
		    {
			if (APU.DSP [reg] & mask)
			    S9xTraceSoundDSP ("%d,", c);
			else
			    S9xTraceSoundDSP ("%d(on),", c);
		    }
#endif
		}
		else
		{
		    type = SOUND_SAMPLE;
#ifdef DEBUGGER
		    if (Settings.TraceSoundDSP)
		    {
			if (APU.DSP [reg] & mask)
			    S9xTraceSoundDSP ("%d(off),", c);
		    }
#endif
		}
		S9xSetSoundType (c, type);
	    }
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("\n");
#endif
	}
	break;
    case APU_MVOL_LEFT:
	if (byte != APU.DSP [APU_MVOL_LEFT])
	{
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] Master volume left:%d\n", 
				  ICPU.Scanline, (signed char) byte);
#endif
		S9xSetMasterVolume ((signed char) byte,
				    (signed char) APU.DSP [APU_MVOL_RIGHT]);
	}
	break;
    case APU_MVOL_RIGHT:
	if (byte != APU.DSP [APU_MVOL_RIGHT])
	{
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] Master volume right:%d\n",
				  ICPU.Scanline, (signed char) byte);
#endif
		S9xSetMasterVolume ((signed char) APU.DSP [APU_MVOL_LEFT],
				    (signed char) byte);
	}
	break;
    case APU_EVOL_LEFT:
	if (byte != APU.DSP [APU_EVOL_LEFT])
	{
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] Echo volume left:%d\n",
				  ICPU.Scanline, (signed char) byte);
#endif
		S9xSetEchoVolume ((signed char) byte,
				  (signed char) APU.DSP [APU_EVOL_RIGHT]);
	}
	break;
    case APU_EVOL_RIGHT:
	if (byte != APU.DSP [APU_EVOL_RIGHT])
	{
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] Echo volume right:%d\n",
				  ICPU.Scanline, (signed char) byte);
#endif
		S9xSetEchoVolume ((signed char) APU.DSP [APU_EVOL_LEFT],
				  (signed char) byte);
	}
	break;
    case APU_ENDX:
#ifdef DEBUGGER
	if (Settings.TraceSoundDSP)
	    S9xTraceSoundDSP ("[%d] Reset ENDX\n", ICPU.Scanline);
#endif
	byte = 0;
	break;

    case APU_KOFF:
	if (byte)
	{
	    uint8 mask = 1;
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] Key off:", ICPU.Scanline);
#endif
	    for (int c = 0; c < 8; c++, mask <<= 1)
	    {
		if ((byte & mask) != 0)
		{
#ifdef DEBUGGER

		    if (Settings.TraceSoundDSP)
			S9xTraceSoundDSP ("%d,", c);
#endif		    
		    if (APU.KeyedChannels & mask)
		    {
			{
			    APU.KeyedChannels &= ~mask;
			    APU.DSP [APU_KON] &= ~mask;
			    //APU.DSP [APU_KOFF] |= mask;
			    S9xSetSoundKeyOff (c);
			}
		    }
		}
	    }
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("\n");
#endif
	}
	APU.DSP [APU_KOFF] = byte;
	return;
    case APU_KON:
	if (byte)
	{
	    uint8 mask = 1;
#ifdef DEBUGGER

	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] Key on:", ICPU.Scanline);
#endif
	    for (int c = 0; c < 8; c++, mask <<= 1)
	    {
		if ((byte & mask) != 0)
		{
#ifdef DEBUGGER
		    if (Settings.TraceSoundDSP)
			S9xTraceSoundDSP ("%d,", c);
#endif		    
		    // Pac-In-Time requires that channels can be key-on
		    // regardeless of their current state.
		    APU.KeyedChannels |= mask;
		    APU.DSP [APU_KON] |= mask;
		    APU.DSP [APU_KOFF] &= ~mask;
		    APU.DSP [APU_ENDX] &= ~mask;
		    S9xPlaySample (c);
		}
	    }
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("\n");
#endif
	}
	return;
	
    case APU_VOL_LEFT + 0x00:
    case APU_VOL_LEFT + 0x10:
    case APU_VOL_LEFT + 0x20:
    case APU_VOL_LEFT + 0x30:
    case APU_VOL_LEFT + 0x40:
    case APU_VOL_LEFT + 0x50:
    case APU_VOL_LEFT + 0x60:
    case APU_VOL_LEFT + 0x70:
// At Shin Megami Tensei suggestion 6/11/00
//	if (byte != APU.DSP [reg])
	{
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] %d volume left: %d\n", 
				  ICPU.Scanline, reg>>4, (signed char) byte);
#endif
		S9xSetSoundVolume (reg >> 4, (signed char) byte,
				   (signed char) APU.DSP [reg + 1]);
	}
	break;
    case APU_VOL_RIGHT + 0x00:
    case APU_VOL_RIGHT + 0x10:
    case APU_VOL_RIGHT + 0x20:
    case APU_VOL_RIGHT + 0x30:
    case APU_VOL_RIGHT + 0x40:
    case APU_VOL_RIGHT + 0x50:
    case APU_VOL_RIGHT + 0x60:
    case APU_VOL_RIGHT + 0x70:
// At Shin Megami Tensei suggestion 6/11/00
//	if (byte != APU.DSP [reg])
	{
#ifdef DEBUGGER
	    if (Settings.TraceSoundDSP)
		S9xTraceSoundDSP ("[%d] %d volume right: %d\n", 
				  ICPU.Scanline, reg >>4, (signed char) byte);
#endif
		S9xSetSoundVolume (reg >> 4, (signed char) APU.DSP [reg - 1],
				   (signed char) byte);
	}
	break;

    case APU_P_LOW + 0x00:
    case APU_P_LOW + 0x10:
    case APU_P_LOW + 0x20:
    case APU_P_LOW + 0x30:
    case APU_P_LOW + 0x40:
    case APU_P_LOW + 0x50:
    case APU_P_LOW + 0x60:
    case APU_P_LOW + 0x70:
#ifdef DEBUGGER
	if (Settings.TraceSoundDSP)
	    S9xTraceSoundDSP ("[%d] %d freq low: %d\n",
			      ICPU.Scanline, reg>>4, byte);
#endif
	    S9xSetSoundHertz (reg >> 4, ((byte + (APU.DSP [reg + 1] << 8)) & FREQUENCY_MASK) * 8);
	break;

    case APU_P_HIGH + 0x00:
    case APU_P_HIGH + 0x10:
    case APU_P_HIGH + 0x20:
    case APU_P_HIGH + 0x30:
    case APU_P_HIGH + 0x40:
    case APU_P_HIGH + 0x50:
    case APU_P_HIGH + 0x60:
    case APU_P_HIGH + 0x70:
#ifdef DEBUGGER
	if (Settings.TraceSoundDSP)
	    S9xTraceSoundDSP ("[%d] %d freq high: %d\n",
			      ICPU.Scanline, reg>>4, byte);
#endif
	    S9xSetSoundHertz (reg >> 4,