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filter.c

#include <math.h>
#include <stdio.h>
#include "types.h"

#include "sound.h"
#include "x6502.h"
#include "fceu.h"
#include "filter.h"

#include "fcoeffs.h"

static uint32 mrindex;
static uint32 mrratio;

void SexyFilter2(int32 *in, int32 count)
{
 #ifdef moo
 static int64 acc=0;
 double x,p;
 int64 c;

 x=2*M_PI*6000/FSettings.SndRate;
 p=((double)2-cos(x)) - sqrt(pow((double)2-cos(x),2) -1 );

 c=p*0x100000;
 //printf("%f\n",(double)c/0x100000);
 #endif
 static int64 acc=0;

 while(count--)
 {
  int64 dropcurrent;
  dropcurrent=((*in<<16)-acc)>>3;

  acc+=dropcurrent;
  *in=acc>>16;
  in++;
  //acc=((int64)0x100000-c)* *in + ((c*acc)>>20);
  //*in=acc>>20;
  //in++;
 }
}

void SexyFilter(int32 *in, int32 *out, int32 count)
{
 static int64 acc1=0,acc2=0;
 int32 mul1,mul2,vmul;

 mul1=(94<<16)/FSettings.SndRate;
 mul2=(24<<16)/FSettings.SndRate;
 vmul=(FSettings.SoundVolume<<16)*3/4/100;

 if(FSettings.soundq) vmul/=4;
 else vmul*=2;                /* TODO:  Increase volume in low quality sound rendering code itself */

 while(count)
 {    
  int64 ino=(int64)*in*vmul;
  acc1+=((ino-acc1)*mul1)>>16;
  acc2+=((ino-acc1-acc2)*mul2)>>16;
  //printf("%d ",*in);
  *in=0;  
  {   
   int32 t=(acc1-ino+acc2)>>16;
   //if(t>32767 || t<-32768) printf("Flow: %d\n",t);
   if(t>32767) t=32767;
   if(t<-32768) t=-32768;   
   *out=t;
  }  
  in++;  
  out++;  
  count--; 
 }
}

/* Returns number of samples written to out. */
/* leftover is set to the number of samples that need to be copied 
   from the end of in to the beginning of in.
*/

//static uint32 mva=1000;

/* This filtering code assumes that almost all input values stay below 32767.
   Do not adjust the volume in the wlookup tables and the expansion sound
   code to be higher, or you *might* overflow the FIR code.
*/

int32 NeoFilterSound(int32 *in, int32 *out, uint32 inlen, int32 *leftover)
{
      uint32 x;
      uint32 max;
      int32 *outsave=out;
      int32 count=0;

//    for(x=0;x<inlen;x++)
//    {
//     if(in[x]>mva){ mva=in[x]; printf("%ld\n",in[x]);}
//    }
        max=(inlen-1)<<16;

      if(FSettings.soundq==2)
         for(x=mrindex;x<max;x+=mrratio)
         {
          int32 acc=0,acc2=0;
          unsigned int c;
          int32 *S,*D;
         
          for(c=SQ2NCOEFFS,S=&in[(x>>16)-SQ2NCOEFFS],D=sq2coeffs;c;c--,D++)
          {
           acc+=(S[c]**D)>>6;
           acc2+=(S[1+c]**D)>>6;
          }

          acc=((int64)acc*(65536-(x&65535))+(int64)acc2*(x&65535))>>(16+11);
          *out=acc;
          out++;   
          count++; 
         }
      else
         for(x=mrindex;x<max;x+=mrratio)
         {
          int32 acc=0,acc2=0;
          unsigned int c;
          int32 *S,*D;
 
          for(c=NCOEFFS,S=&in[(x>>16)-NCOEFFS],D=coeffs;c;c--,D++)
        {
         acc+=(S[c]**D)>>6;
         acc2+=(S[1+c]**D)>>6;
        }
 
          acc=((int64)acc*(65536-(x&65535))+(int64)acc2*(x&65535))>>(16+11);  
          *out=acc;
          out++;
          count++;
         }
        mrindex=x-max;

      if(FSettings.soundq==2)
      {
         mrindex+=SQ2NCOEFFS*65536;
         *leftover=SQ2NCOEFFS+1;
      }
      else
      {
         mrindex+=NCOEFFS*65536;
         *leftover=NCOEFFS+1;
      }

      if(GameExpSound.NeoFill)
       GameExpSound.NeoFill(outsave,count);

      SexyFilter(outsave,outsave,count);
      if(FSettings.lowpass)
       SexyFilter2(outsave,count);
      return(count);
}

void MakeFilters(int32 rate)
{
 int32 *tabs[6]={C44100NTSC,C44100PAL,C48000NTSC,C48000PAL,C96000NTSC,
        C96000PAL};
 int32 *sq2tabs[6]={SQ2C44100NTSC,SQ2C44100PAL,SQ2C48000NTSC,SQ2C48000PAL,
      SQ2C96000NTSC,SQ2C96000PAL};

 int32 *tmp;
 int32 x;
 uint32 nco;

 if(FSettings.soundq==2)
  nco=SQ2NCOEFFS;
 else
  nco=NCOEFFS;

 mrindex=(nco+1)<<16;
 mrratio=(PAL?(int64)(PAL_CPU*65536):(int64)(NTSC_CPU*65536))/rate;

 if(FSettings.soundq==2)
  tmp=sq2tabs[(PAL?1:0)|(rate==48000?2:0)|(rate==96000?4:0)];
 else
  tmp=tabs[(PAL?1:0)|(rate==48000?2:0)|(rate==96000?4:0)];

 if(FSettings.soundq==2)
  for(x=0;x<SQ2NCOEFFS>>1;x++)
   sq2coeffs[x]=sq2coeffs[SQ2NCOEFFS-1-x]=tmp[x];
 else
  for(x=0;x<NCOEFFS>>1;x++)
   coeffs[x]=coeffs[NCOEFFS-1-x]=tmp[x];

 #ifdef MOO
 /* Some tests involving precision and error. */
 {
  static int64 acc=0;
  int x;
  for(x=0;x<SQ2NCOEFFS;x++)
   acc+=(int64)32767*sq2coeffs[x];
  printf("Foo: %lld\n",acc);
 }
 #endif
}

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