fceugx/source/sound.c

/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2002 Xodnizel
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <stdlib.h>
#include <stdio.h>

#include <string.h>

#include "types.h"
#include "x6502.h"

#include "fceu.h"
#include "sound.h"
#include "filter.h"
#include "state.h"
#include "wave.h"

static uint32 wlookup1[32];
static uint32 wlookup2[203];

int32 Wave[2048+512];
int32 WaveHi[40000];
int32 WaveFinal[2048+512];

EXPSOUND GameExpSound={0,0,0};

static uint8 TriCount;
static uint8 TriMode;

static int32 tristep;

static int32 wlcount[4];  /* Wave length counters.  */

static uint8 IRQFrameMode;  /* $4017 / xx000000 */
static uint8 PSG[0x10];
static uint8 RawDALatch;  /* $4011 0xxxxxxx */

uint8 EnabledChannels;    /* Byte written to $4015 */

typedef struct {
  uint8 Speed;
  uint8 Mode;  /* Fixed volume(1), and loop(2) */
  uint8 DecCountTo1;
  uint8 decvolume;
  int reloaddec;
} ENVUNIT;

static ENVUNIT EnvUnits[3];

static const int RectDuties[4]={1,2,4,6};

static int32 RectDutyCount[2];
static uint8 sweepon[2];
static int32 curfreq[2];
static uint8 SweepCount[2];

static uint16 nreg;

static uint8 fcnt;
static int32 fhcnt;
static int32 fhinc;

uint32 soundtsoffs;

/* Variables exclusively for low-quality sound. */
int32 nesincsize;
uint32 soundtsinc;
uint32 soundtsi;
static int32 sqacc[2];
/* LQ variables segment ends. */

static int32 lengthcount[4];
static const uint8 lengthtable[0x20]=
{
 0x5*2,0x7f*2,0xA*2,0x1*2,0x14*2,0x2*2,0x28*2,0x3*2,0x50*2,0x4*2,0x1E*2,0x5*2,0x7*2,0x6*2,0x0E*2,0x7*2,
 0x6*2,0x08*2,0xC*2,0x9*2,0x18*2,0xa*2,0x30*2,0xb*2,0x60*2,0xc*2,0x24*2,0xd*2,0x8*2,0xe*2,0x10*2,0xf*2
};

static const uint32 NoiseFreqTable[0x10]=
{
 2,4,8,0x10,0x20,0x30,0x40,0x50,0x65,0x7f,0xbe,0xfe,0x17d,0x1fc,0x3f9,0x7f2
};

static const uint32 NTSCDMCTable[0x10]=
{
 428,380,340,320,286,254,226,214,
 190,160,142,128,106, 84 ,72,54
};

static const uint32 PALDMCTable[0x10]=
{
 397, 353, 315, 297, 265, 235, 209, 198,
 176, 148, 131, 118, 98, 78, 66, 50,
};

// $4010  -  Frequency
// $4011  -  Actual data outputted
// $4012  -  Address register: $c000 + V*64
// $4013  -  Size register:  Size in bytes = (V+1)*64

static int32 DMCacc=1;
static int32 DMCPeriod;
static uint8 DMCBitCount=0;

static uint8 DMCAddressLatch,DMCSizeLatch; /* writes to 4012 and 4013 */
static uint8 DMCFormat;  /* Write to $4010 */

static uint32 DMCAddress=0;
static int32 DMCSize=0;
static uint8 DMCShift=0;
static uint8 SIRQStat=0;

static char DMCHaveDMA=0;
static uint8 DMCDMABuf=0;
static char DMCHaveSample=0;

static void Dummyfunc(void) {};
static void (*DoNoise)(void)=Dummyfunc;
static void (*DoTriangle)(void)=Dummyfunc;
static void (*DoPCM)(void)=Dummyfunc;
static void (*DoSQ1)(void)=Dummyfunc;
static void (*DoSQ2)(void)=Dummyfunc;

static uint32 ChannelBC[5];

static void LoadDMCPeriod(uint8 V)
{
 if(PAL)
  DMCPeriod=PALDMCTable[V];
 else
  DMCPeriod=NTSCDMCTable[V];
}

static void PrepDPCM()
{
 DMCAddress=0x4000+(DMCAddressLatch<<6);
 DMCSize=(DMCSizeLatch<<4)+1;
}

/* Instantaneous?  Maybe the new freq value is being calculated all of the time... */

static int FASTAPASS(2) CheckFreq(uint32 cf, uint8 sr)
{
 uint32 mod;
 if(!(sr&0x8))
 {
  mod=cf>>(sr&7);
  if((mod+cf)&0x800)
   return(0);
 }
 return(1);
}

static void SQReload(int x, uint8 V)
{
     if(EnabledChannels&(1<<x))
     {
      if(x)
       DoSQ2();
      else
       DoSQ1();
      lengthcount[x]=lengthtable[(V>>3)&0x1f];
     }

     sweepon[x]=PSG[(x<<2)|1]&0x80;
     curfreq[x]=PSG[(x<<2)|0x2]|((V&7)<<8);
     SweepCount[x]=((PSG[(x<<2)|0x1]>>4)&7)+1;

     RectDutyCount[x]=7;
     EnvUnits[x].reloaddec=1;
     //reloadfreq[x]=1;
}

static DECLFW(Write_PSG)
{
 A&=0x1F;
 switch(A)
 {
  case 0x0:DoSQ1();
     EnvUnits[0].Mode=(V&0x30)>>4;
     EnvUnits[0].Speed=(V&0xF);
     break;
  case 0x1:
     sweepon[0]=V&0x80;
     break;
  case 0x2:
     DoSQ1();
     curfreq[0]&=0xFF00;
     curfreq[0]|=V;
     break;
  case 0x3:
     SQReload(0,V);
     break;
  case 0x4:
     DoSQ2();
     EnvUnits[1].Mode=(V&0x30)>>4;
     EnvUnits[1].Speed=(V&0xF);
     break;
  case 0x5:
    sweepon[1]=V&0x80;
    break;
  case 0x6:DoSQ2();
    curfreq[1]&=0xFF00;
    curfreq[1]|=V;
    break;
  case 0x7:
    SQReload(1,V);
    break;
  case 0xa:DoTriangle();
     break;
  case 0xb:
    DoTriangle();
    if(EnabledChannels&0x4)
     lengthcount[2]=lengthtable[(V>>3)&0x1f];
    TriMode=1;  // Load mode
    break;
  case 0xC:DoNoise();
     EnvUnits[2].Mode=(V&0x30)>>4;
     EnvUnits[2].Speed=(V&0xF);
     break;
  case 0xE:DoNoise();
     break;
  case 0xF:
     DoNoise();
     if(EnabledChannels&0x8)
      lengthcount[3]=lengthtable[(V>>3)&0x1f];
     EnvUnits[2].reloaddec=1;
     break;
 case 0x10:DoPCM();
     LoadDMCPeriod(V&0xF);

     if(SIRQStat&0x80)
     {
      if(!(V&0x80))
      {
       X6502_IRQEnd(FCEU_IQDPCM);
        SIRQStat&=~0x80;
      }
      else X6502_IRQBegin(FCEU_IQDPCM);
     }
     break;
 }
 PSG[A]=V;
}

static DECLFW(Write_DMCRegs)
{
 A&=0xF;

 switch(A)
 {
  case 0x00:DoPCM();
      LoadDMCPeriod(V&0xF);

      if(SIRQStat&0x80)
      {
       if(!(V&0x80))
       {
        X6502_IRQEnd(FCEU_IQDPCM);
        SIRQStat&=~0x80;
       }
       else X6502_IRQBegin(FCEU_IQDPCM);
      }
      DMCFormat=V;
      break;
  case 0x01:DoPCM();
      RawDALatch=V&0x7F;
      break;
  case 0x02:DMCAddressLatch=V;break;
  case 0x03:DMCSizeLatch=V;break;
 }


}

static DECLFW(StatusWrite)
{
  int x;

  DoSQ1();
  DoSQ2();
  DoTriangle();
  DoNoise();
  DoPCM();
  for(x=0;x<4;x++)
   if(!(V&(1<<x))) lengthcount[x]=0;   /* Force length counters to 0. */

  if(V&0x10)
  {
   if(!DMCSize)
    PrepDPCM();
  }
  else
  {
   DMCSize=0;
  }
  SIRQStat&=~0x80;
  X6502_IRQEnd(FCEU_IQDPCM);
  EnabledChannels=V&0x1F;
}

static DECLFR(StatusRead)
{
   int x;
   uint8 ret;

   ret=SIRQStat;

   for(x=0;x<4;x++) ret|=lengthcount[x]?(1<<x):0;
   if(DMCSize) ret|=0x10;

   #ifdef FCEUDEF_DEBUGGER
   if(!fceuindbg)
   #endif
   {
    SIRQStat&=~0x40;
    X6502_IRQEnd(FCEU_IQFCOUNT);
   }
   return ret;
}

static void FASTAPASS(1) FrameSoundStuff(int V)
{
 int P;

 DoSQ1();
 DoSQ2();
 DoNoise();
 DoTriangle();

 if(!(V&1)) /* Envelope decay, linear counter, length counter, freq sweep */
 {
  if(!(PSG[8]&0x80))
   if(lengthcount[2]>0)
    lengthcount[2]--;

  if(!(PSG[0xC]&0x20))  /* Make sure loop flag is not set. */
   if(lengthcount[3]>0)
    lengthcount[3]--;

  for(P=0;P<2;P++)
  {
   if(!(PSG[P<<2]&0x20))  /* Make sure loop flag is not set. */
    if(lengthcount[P]>0)
     lengthcount[P]--;

   /* Frequency Sweep Code Here */
   /* xxxx 0000 */
   /* xxxx = hz.  120/(x+1)*/
   if(sweepon[P])
   {
    int32 mod=0;

    if(SweepCount[P]>0) SweepCount[P]--;
    if(SweepCount[P]<=0)
    {
     SweepCount[P]=((PSG[(P<<2)+0x1]>>4)&7)+1; //+1;
     if(PSG[(P<<2)+0x1]&0x8)
     {
      mod-=(P^1)+((curfreq[P])>>(PSG[(P<<2)+0x1]&7));
      if(curfreq[P] && (PSG[(P<<2)+0x1]&7)/* && sweepon[P]&0x80*/)
      {
       curfreq[P]+=mod;
      }
     }
     else
     {
      mod=curfreq[P]>>(PSG[(P<<2)+0x1]&7);
      if((mod+curfreq[P])&0x800)
      {
       sweepon[P]=0;
       curfreq[P]=0;
      }
      else
      {
       if(curfreq[P] && (PSG[(P<<2)+0x1]&7)/* && sweepon[P]&0x80*/)
       {
  curfreq[P]+=mod;
       }
      }
     }
    }
   }
   else  /* Sweeping is disabled: */
   {
    //curfreq[P]&=0xFF00;
    //curfreq[P]|=PSG[(P<<2)|0x2]; //|((PSG[(P<<2)|3]&7)<<8);
   }
  }
 }

 /* Now do envelope decay + linear counter. */

  if(TriMode) // In load mode?
   TriCount=PSG[0x8]&0x7F;
  else if(TriCount)
   TriCount--;

  if(!(PSG[0x8]&0x80))
   TriMode=0;

  for(P=0;P<3;P++)
  {
   if(EnvUnits[P].reloaddec)
   {
    EnvUnits[P].decvolume=0xF;
    EnvUnits[P].DecCountTo1=EnvUnits[P].Speed+1;
    EnvUnits[P].reloaddec=0;
    continue;
   }

   if(EnvUnits[P].DecCountTo1>0) EnvUnits[P].DecCountTo1--;
   if(EnvUnits[P].DecCountTo1==0)
   {
    EnvUnits[P].DecCountTo1=EnvUnits[P].Speed+1;
    if(EnvUnits[P].decvolume || (EnvUnits[P].Mode&0x2))
    {
     EnvUnits[P].decvolume--;
     EnvUnits[P].decvolume&=0xF;
    }
   }
  }
}

void FrameSoundUpdate(void)
{
 // Linear counter:  Bit 0-6 of $4008
 // Length counter:  Bit 4-7 of $4003, $4007, $400b, $400f

 if(!fcnt && !(IRQFrameMode&0x3))
 {
   SIRQStat|=0x40;
   X6502_IRQBegin(FCEU_IQFCOUNT);
 }

 if(fcnt==3)
 {
  if(IRQFrameMode&0x2)
   fhcnt+=fhinc;
 }
 FrameSoundStuff(fcnt);
 fcnt=(fcnt+1)&3;
}


static INLINE void tester(void)
{
 if(DMCBitCount==0)
 {
  if(!DMCHaveDMA)
   DMCHaveSample=0;
  else
  {
   DMCHaveSample=1;
   DMCShift=DMCDMABuf;
   DMCHaveDMA=0;
  }
 }
}

static INLINE void DMCDMA(void)
{
  if(DMCSize && !DMCHaveDMA)
  {
   X6502_DMR(0x8000+DMCAddress);
   X6502_DMR(0x8000+DMCAddress);
   X6502_DMR(0x8000+DMCAddress);
   DMCDMABuf=X6502_DMR(0x8000+DMCAddress);
   DMCHaveDMA=1;
   DMCAddress=(DMCAddress+1)&0x7fff;
   DMCSize--;
   if(!DMCSize)
   {
    if(DMCFormat&0x40)
     PrepDPCM();
    else
    {
     SIRQStat|=0x80;
     if(DMCFormat&0x80)
      X6502_IRQBegin(FCEU_IQDPCM);
    }
   }
 }
}

void FASTAPASS(1) FCEU_SoundCPUHook(int cycles)
{
 fhcnt-=cycles*48;
 if(fhcnt<=0)
 {
  FrameSoundUpdate();
  fhcnt+=fhinc;
 }

 DMCDMA();
 DMCacc-=cycles;

 while(DMCacc<=0)
 {
  if(DMCHaveSample)
  {
   uint8 bah=RawDALatch;
   int t=((DMCShift&1)<<2)-2;

   /* Unbelievably ugly hack */
   if(FSettings.SndRate)
   {
    soundtsoffs+=DMCacc;
    DoPCM();
    soundtsoffs-=DMCacc;
   }
   RawDALatch+=t;
   if(RawDALatch&0x80)
    RawDALatch=bah;
  }

  DMCacc+=DMCPeriod;
  DMCBitCount=(DMCBitCount+1)&7;
  DMCShift>>=1;
  tester();
 }
}

void RDoPCM(void)
{
 int32 V;

 for(V=ChannelBC[4];V<SOUNDTS;V++)
  WaveHi[V]+=RawDALatch<<16;

 ChannelBC[4]=SOUNDTS;
}

/* This has the correct phase.  Don't mess with it. */
static INLINE void RDoSQ(int x)
{
   int32 V;
   int32 amp;
   int32 rthresh;
   int32 *D;
   int32 currdc;
   int32 cf;
   int32 rc;

   if(curfreq[x]<8 || curfreq[x]>0x7ff)
    goto endit;
   if(!CheckFreq(curfreq[x],PSG[(x<<2)|0x1]))
    goto endit;
   if(!lengthcount[x])
    goto endit;

   if(EnvUnits[x].Mode&0x1)
    amp=EnvUnits[x].Speed;
   else
    amp=EnvUnits[x].decvolume;
//   printf("%d\n",amp);
   amp<<=24;

   rthresh=RectDuties[(PSG[(x<<2)]&0xC0)>>6];

   D=&WaveHi[ChannelBC[x]];
   V=SOUNDTS-ChannelBC[x];

   currdc=RectDutyCount[x];
   cf=(curfreq[x]+1)*2;
   rc=wlcount[x];

   while(V>0)
   {
    if(currdc<rthresh)
     *D+=amp;
    rc--;
    if(!rc)
    {
     rc=cf;
     currdc=(currdc+1)&7;
    }
    V--;
    D++;
   }

   RectDutyCount[x]=currdc;
   wlcount[x]=rc;

   endit:
   ChannelBC[x]=SOUNDTS;
}

static void RDoSQ1(void)
{
 RDoSQ(0);
}

static void RDoSQ2(void)
{
 RDoSQ(1);
}

static void RDoSQLQ(void)
{
   int32 start,end;
   int32 V;
   int32 amp[2];
   int32 rthresh[2];
   int32 freq[2];
   int x;
   int32 inie[2];

   int32 ttable[2][8];
   int32 totalout;

   start=ChannelBC[0];
   end=(SOUNDTS<<16)/soundtsinc;
   if(end<=start) return;
   ChannelBC[0]=end;

   for(x=0;x<2;x++)
   {
    int y;

    inie[x]=nesincsize;
    if(curfreq[x]<8 || curfreq[x]>0x7ff)
     inie[x]=0;
    if(!CheckFreq(curfreq[x],PSG[(x<<2)|0x1]))
     inie[x]=0;
    if(!lengthcount[x])
     inie[x]=0;

    if(EnvUnits[x].Mode&0x1)
     amp[x]=EnvUnits[x].Speed;
    else
     amp[x]=EnvUnits[x].decvolume;

    if(!inie[x]) amp[x]=0;    /* Correct? Buzzing in MM2, others otherwise... */

    rthresh[x]=RectDuties[(PSG[x*4]&0xC0)>>6];

    for(y=0;y<8;y++)
    {
     if(y < rthresh[x])
      ttable[x][y] = amp[x];
     else
      ttable[x][y] = 0;
    }
    freq[x]=(curfreq[x]+1)<<1;
    freq[x]<<=17;
   }

   totalout = wlookup1[ ttable[0][RectDutyCount[0]] + ttable[1][RectDutyCount[1]] ];

   if(!inie[0] && !inie[1])
   {
   for(V=start;V<end;V++)
     Wave[V>>4]+=totalout;
   }
   else
   for(V=start;V<end;V++)
   {
    //int tmpamp=0;
    //if(RectDutyCount[0]<rthresh[0])
    // tmpamp=amp[0];
    //if(RectDutyCount[1]<rthresh[1])
    // tmpamp+=amp[1];
    //tmpamp=wlookup1[tmpamp];
    //tmpamp = wlookup1[ ttable[0][RectDutyCount[0]] + ttable[1][RectDutyCount[1]] ];

    Wave[V>>4]+=totalout; //tmpamp;

    sqacc[0]-=inie[0];
    sqacc[1]-=inie[1];

    if(sqacc[0]<=0)
    {
     rea:
     sqacc[0]+=freq[0];
     RectDutyCount[0]=(RectDutyCount[0]+1)&7;
     if(sqacc[0]<=0) goto rea;
     totalout = wlookup1[ ttable[0][RectDutyCount[0]] + ttable[1][RectDutyCount[1]] ];
    }

    if(sqacc[1]<=0)
    {
     rea2:
     sqacc[1]+=freq[1];
     RectDutyCount[1]=(RectDutyCount[1]+1)&7;
     if(sqacc[1]<=0) goto rea2;
     totalout = wlookup1[ ttable[0][RectDutyCount[0]] + ttable[1][RectDutyCount[1]] ];
    }
   }
}

static void RDoTriangle(void)
{
 int32 V;
 int32 tcout;

 tcout=(tristep&0xF);
 if(!(tristep&0x10)) tcout^=0xF;
 tcout=(tcout*3) << 16;  //(tcout<<1);

 if(!lengthcount[2] || !TriCount)
 {           /* Counter is halted, but we still need to output. */
  int32 *start = &WaveHi[ChannelBC[2]];
  int32 count = SOUNDTS - ChannelBC[2];
  while(count--)
  {
   *start += tcout;
   start++;
  }
  //for(V=ChannelBC[2];V<SOUNDTS;V++)
  // WaveHi[V]+=tcout;
 }
 else
  for(V=ChannelBC[2];V<SOUNDTS;V++)
  {
    WaveHi[V]+=tcout;
    wlcount[2]--;
    if(!wlcount[2])
    {
     wlcount[2]=(PSG[0xa]|((PSG[0xb]&7)<<8))+1;
     tristep++;
     tcout=(tristep&0xF);
     if(!(tristep&0x10)) tcout^=0xF;
     tcout=(tcout*3) << 16;
    }
  }

 ChannelBC[2]=SOUNDTS;
}

static void RDoTriangleNoisePCMLQ(void)
{
   static uint32 tcout=0;
   static int32 triacc=0;
   static int32 noiseacc=0;

   int32 V;
   int32 start,end;
   int32 freq[2];
   int32 inie[2];
   uint32 amptab[2];
   uint32 noiseout;
   int nshift;

   int32 totalout;

   start=ChannelBC[2];
   end=(SOUNDTS<<16)/soundtsinc;
   if(end<=start) return;
   ChannelBC[2]=end;

   inie[0]=inie[1]=nesincsize;

   freq[0]=(((PSG[0xa]|((PSG[0xb]&7)<<8))+1));

   if(!lengthcount[2] || !TriCount || freq[0]<=4)
    inie[0]=0;

   freq[0]<<=17;
   if(EnvUnits[2].Mode&0x1)
    amptab[0]=EnvUnits[2].Speed;
   else
    amptab[0]=EnvUnits[2].decvolume;
   amptab[1]=0;
   amptab[0]<<=1;

   if(!lengthcount[3])
    amptab[0]=inie[1]=0;  /* Quick hack speedup, set inie[1] to 0 */

   noiseout=amptab[(nreg>>0xe)&1];

   if(PSG[0xE]&0x80)
    nshift=8;
   else
    nshift=13;


   totalout = wlookup2[tcout+noiseout+RawDALatch];

   if(inie[0] && inie[1])
   {
   for(V=start;V<end;V++)
   {
     Wave[V>>4]+=totalout;

    triacc-=inie[0];
    noiseacc-=inie[1];

    if(triacc<=0)
    {
     rea:
     triacc+=freq[0]; //t;
     tristep=(tristep+1)&0x1F;
     if(triacc<=0) goto rea;
     tcout=(tristep&0xF);
     if(!(tristep&0x10)) tcout^=0xF;
     tcout=tcout*3;
      totalout = wlookup2[tcout+noiseout+RawDALatch];
    }

    if(noiseacc<=0)
    {
     rea2:
     noiseacc+=NoiseFreqTable[PSG[0xE]&0xF]<<(16+2);
     nreg=(nreg<<1)+(((nreg>>nshift)^(nreg>>14))&1);
     nreg&=0x7fff;
     noiseout=amptab[(nreg>>0xe)];
     if(noiseacc<=0) goto rea2;
      totalout = wlookup2[tcout+noiseout+RawDALatch];
    } /* noiseacc<=0 */
  } /* for(V=... */
}
  else if(inie[0])
  {
    for(V=start;V<end;V++)
    {
     Wave[V>>4]+=totalout;

     triacc-=inie[0];

     if(triacc<=0)
     {
      area:
      triacc+=freq[0]; //t;
      tristep=(tristep+1)&0x1F;
      if(triacc<=0) goto area;
      tcout=(tristep&0xF);
      if(!(tristep&0x10)) tcout^=0xF;
      tcout=tcout*3;
      totalout = wlookup2[tcout+noiseout+RawDALatch];
     }
    }
  }
  else if(inie[1])
  {
    for(V=start;V<end;V++)
    {
     Wave[V>>4]+=totalout;
     noiseacc-=inie[1];
     if(noiseacc<=0)
     {
      area2:
      noiseacc+=NoiseFreqTable[PSG[0xE]&0xF]<<(16+2);
      nreg=(nreg<<1)+(((nreg>>nshift)^(nreg>>14))&1);
      nreg&=0x7fff;
      noiseout=amptab[(nreg>>0xe)];
      if(noiseacc<=0) goto area2;
      totalout = wlookup2[tcout+noiseout+RawDALatch];
     } /* noiseacc<=0 */
    }
  }
  else
  {
    for(V=start;V<end;V++)
     Wave[V>>4]+=totalout;
  }
}


static void RDoNoise(void)
{
 int32 V;
 int32 outo;
 uint32 amptab[2];

 if(EnvUnits[2].Mode&0x1)
  amptab[0]=EnvUnits[2].Speed;
 else
  amptab[0]=EnvUnits[2].decvolume;

 amptab[0]<<=16;
 amptab[1]=0;

 amptab[0]<<=1;

 outo=amptab[nreg&1]; //(nreg>>0xe)&1];

 if(!lengthcount[3])
 {
  outo=amptab[0]=0;
 }

 if(PSG[0xE]&0x80)  // "short" noise
  for(V=ChannelBC[3];V<SOUNDTS;V++)
  {
   WaveHi[V]+=outo;
   wlcount[3]--;
   if(!wlcount[3])
   {
    uint8 feedback;
    wlcount[3]=NoiseFreqTable[PSG[0xE]&0xF]<<1;
    feedback=((nreg>>8)&1)^((nreg>>14)&1);
    nreg=(nreg<<1)+feedback;
    nreg&=0x7fff;
    outo=amptab[(nreg>>0xe)&1];
   }
  }
 else
  for(V=ChannelBC[3];V<SOUNDTS;V++)
  {
   WaveHi[V]+=outo;
   wlcount[3]--;
   if(!wlcount[3])
   {
    uint8 feedback;
    wlcount[3]=NoiseFreqTable[PSG[0xE]&0xF]<<1;
    feedback=((nreg>>13)&1)^((nreg>>14)&1);
    nreg=(nreg<<1)+feedback;
    nreg&=0x7fff;
    outo=amptab[(nreg>>0xe)&1];
   }
  }
 ChannelBC[3]=SOUNDTS;
}

DECLFW(Write_IRQFM)
{
 V=(V&0xC0)>>6;
 fcnt=0;
 if(V&0x2)
  FrameSoundUpdate();
 fcnt=1;
 fhcnt=fhinc;
 X6502_IRQEnd(FCEU_IQFCOUNT);
 SIRQStat&=~0x40;
 IRQFrameMode=V;
}

void SetNESSoundMap(void)
{
  SetWriteHandler(0x4000,0x400F,Write_PSG);
  SetWriteHandler(0x4010,0x4013,Write_DMCRegs);
  SetWriteHandler(0x4017,0x4017,Write_IRQFM);

  SetWriteHandler(0x4015,0x4015,StatusWrite);
  SetReadHandler(0x4015,0x4015,StatusRead);
}

static int32 inbuf=0;
int FlushEmulateSound(void)
{
  int x;
  int32 end,left;

  if(!timestamp) return(0);

  if(!FSettings.SndRate)
  {
   left=0;
   end=0;
   goto nosoundo;
  }

  DoSQ1();
  DoSQ2();
  DoTriangle();
  DoNoise();
  DoPCM();

  if(FSettings.soundq>=1)
  {
   int32 *tmpo=&WaveHi[soundtsoffs];

   if(GameExpSound.HiFill) GameExpSound.HiFill();

   for(x=timestamp;x;x--)
   {
    uint32 b=*tmpo;
    *tmpo=(b&65535)+wlookup2[(b>>16)&255]+wlookup1[b>>24];
    tmpo++;
   }
   end=NeoFilterSound(WaveHi,WaveFinal,SOUNDTS,&left);

   memmove(WaveHi,WaveHi+SOUNDTS-left,left*sizeof(uint32));
   memset(WaveHi+left,0,sizeof(WaveHi)-left*sizeof(uint32));

   if(GameExpSound.HiSync) GameExpSound.HiSync(left);
   for(x=0;x<5;x++)
    ChannelBC[x]=left;
  }
  else
  {
   end=(SOUNDTS<<16)/soundtsinc;
   if(GameExpSound.Fill)
    GameExpSound.Fill(end&0xF);

   SexyFilter(Wave,WaveFinal,end>>4);

   //if(FSettings.lowpass)
   // SexyFilter2(WaveFinal,end>>4);
   if(end&0xF)
    Wave[0]=Wave[(end>>4)];
   Wave[end>>4]=0;
  }
  nosoundo:

  if(FSettings.soundq>=1)
  {
   soundtsoffs=left;
  }
  else
  {
   for(x=0;x<5;x++)
    ChannelBC[x]=end&0xF;
   soundtsoffs = (soundtsinc*(end&0xF))>>16;
   end>>=4;
  }
  inbuf=end;

  FCEU_WriteWaveData(WaveFinal, end); /* This function will just return
            if sound recording is off. */
  return(end);
}

int GetSoundBuffer(int32 **W)
{
 *W=WaveFinal;
 return(inbuf);
}

/* FIXME:  Find out what sound registers get reset on reset.  I know $4001/$4005 don't,
due to that whole MegaMan 2 Game Genie thing.
*/

void FCEUSND_Reset(void)
{
  int x;

  IRQFrameMode=0x0;
  fhcnt=fhinc;
  fcnt=0;

  nreg=1;
  for(x=0;x<2;x++)
  {
   wlcount[x]=2048;
   if(nesincsize) // lq mode
    sqacc[x]=((uint32)2048<<17)/nesincsize;
   else
    sqacc[x]=1;
   sweepon[x]=0;
   curfreq[x]=0;
  }
  wlcount[2]=1;  //2048;
  wlcount[3]=2048;
  DMCHaveDMA=DMCHaveSample=0;
  SIRQStat=0x00;

  RawDALatch=0x00;
  TriCount=0;
  TriMode=0;
  tristep=0;
  EnabledChannels=0;
  for(x=0;x<4;x++)
   lengthcount[x]=0;

  DMCAddressLatch=0;
  DMCSizeLatch=0;
  DMCFormat=0;
  DMCAddress=0;
  DMCSize=0;
  DMCShift=0;
}

void FCEUSND_Power(void)
{
  int x;

  SetNESSoundMap();
  memset(PSG,0x00,sizeof(PSG));
  FCEUSND_Reset();

  memset(Wave,0,sizeof(Wave));
  memset(WaveHi,0,sizeof(WaveHi));
  memset(&EnvUnits,0,sizeof(EnvUnits));

  for(x=0;x<5;x++)
   ChannelBC[x]=0;
  soundtsoffs=0;
  LoadDMCPeriod(DMCFormat&0xF);
}


void SetSoundVariables(void)
{
  int x;

  fhinc=PAL?16626:14915;  // *2 CPU clock rate
  fhinc*=24;

  if(FSettings.SndRate)
  {
   wlookup1[0]=0;
   for(x=1;x<32;x++)
   {
    wlookup1[x]=(double)16*16*16*4*95.52/((double)8128/(double)x+100);
    if(!FSettings.soundq) wlookup1[x]>>=4;
   }
   wlookup2[0]=0;
   for(x=1;x<203;x++)
   {
    wlookup2[x]=(double)16*16*16*4*163.67/((double)24329/(double)x+100);
    if(!FSettings.soundq) wlookup2[x]>>=4;
   }
   if(FSettings.soundq>=1)
   {
    DoNoise=RDoNoise;
    DoTriangle=RDoTriangle;
    DoPCM=RDoPCM;
    DoSQ1=RDoSQ1;
    DoSQ2=RDoSQ2;
   }
   else
   {
    DoNoise=DoTriangle=DoPCM=DoSQ1=DoSQ2=Dummyfunc;
    DoSQ1=RDoSQLQ;
    DoSQ2=RDoSQLQ;
    DoTriangle=RDoTriangleNoisePCMLQ;
    DoNoise=RDoTriangleNoisePCMLQ;
    DoPCM=RDoTriangleNoisePCMLQ;
   }
  }
  else
  {
   DoNoise=DoTriangle=DoPCM=DoSQ1=DoSQ2=Dummyfunc;
   return;
  }

  MakeFilters(FSettings.SndRate);

  if(GameExpSound.RChange)
   GameExpSound.RChange();

  nesincsize=(int64)(((int64)1<<17)*(double)(PAL?PAL_CPU:NTSC_CPU)/(FSettings.SndRate * 16));
  memset(sqacc,0,sizeof(sqacc));
  memset(ChannelBC,0,sizeof(ChannelBC));

  LoadDMCPeriod(DMCFormat&0xF);  // For changing from PAL to NTSC

  soundtsinc=(uint32)((uint64)(PAL?(long double)PAL_CPU*65536:(long double)NTSC_CPU*65536)/(FSettings.SndRate * 16));
}

void FCEUI_Sound(int Rate)
{
 FSettings.SndRate=Rate;
 SetSoundVariables();
}

void FCEUI_SetLowPass(int q)
{
 FSettings.lowpass=q;
}

void FCEUI_SetSoundQuality(int quality)
{
 FSettings.soundq=quality;
 SetSoundVariables();
}

void FCEUI_SetSoundVolume(uint32 volume)
{
 FSettings.SoundVolume=volume;
}


SFORMAT FCEUSND_STATEINFO[]={

 { &fhcnt, 4|FCEUSTATE_RLSB,"FHCN"},
 { &fcnt, 1, "FCNT"},
 { PSG, 0x10, "PSG"},
 { &EnabledChannels, 1, "ENCH"},
 { &IRQFrameMode, 1, "IQFM"},
 { &nreg, 2|FCEUSTATE_RLSB, "NREG"},
 { &TriMode, 1, "TRIM"},
 { &TriCount, 1, "TRIC"},

 { &EnvUnits[0].Speed, 1, "E0SP"},
 { &EnvUnits[1].Speed, 1, "E1SP"},
 { &EnvUnits[2].Speed, 1, "E2SP"},

 { &EnvUnits[0].Mode, 1, "E0MO"},
 { &EnvUnits[1].Mode, 1, "E1MO"},
 { &EnvUnits[2].Mode, 1, "E2MO"},

 { &EnvUnits[0].DecCountTo1, 1, "E0D1"},
 { &EnvUnits[1].DecCountTo1, 1, "E1D1"},
 { &EnvUnits[2].DecCountTo1, 1, "E2D1"},

 { &EnvUnits[0].decvolume, 1, "E0DV"},
 { &EnvUnits[1].decvolume, 1, "E1DV"},
 { &EnvUnits[2].decvolume, 1, "E2DV"},

 { &lengthcount[0], 4|FCEUSTATE_RLSB, "LEN0"},
 { &lengthcount[1], 4|FCEUSTATE_RLSB, "LEN1"},
 { &lengthcount[2], 4|FCEUSTATE_RLSB, "LEN2"},
 { &lengthcount[3], 4|FCEUSTATE_RLSB, "LEN3"},
 { sweepon, 2, "SWEE"},
 { &curfreq[0], 4|FCEUSTATE_RLSB,"CRF1"},
 { &curfreq[1], 4|FCEUSTATE_RLSB,"CRF2"},
 { SweepCount, 2,"SWCT"},

 { &SIRQStat, 1, "SIRQ"},

 { &DMCacc, 4|FCEUSTATE_RLSB, "5ACC"},
 { &DMCBitCount, 1, "5BIT"},
 { &DMCAddress, 4|FCEUSTATE_RLSB, "5ADD"},
 { &DMCSize, 4|FCEUSTATE_RLSB, "5SIZ"},
 { &DMCShift, 1, "5SHF"},

 { &DMCHaveDMA, 1, "5HVDM"},
 { &DMCHaveSample, 1, "5HVSP"},

 { &DMCSizeLatch, 1, "5SZL"},
 { &DMCAddressLatch, 1, "5ADL"},
 { &DMCFormat, 1, "5FMT"},
 { &RawDALatch, 1, "RWDA"},
 { 0 }
};

void FCEUSND_SaveState(void)
{

}

void FCEUSND_LoadState(int version)
{
 LoadDMCPeriod(DMCFormat&0xF);
 RawDALatch&=0x7F;
 DMCAddress&=0x7FFF;
}