/*
 * Mpeg Layer-1,2,3 audio decoder
 * ------------------------------
 * copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved.
 * See also 'README'
 *
 * slighlty optimized for machines without autoincrement/decrement.
 * The performance is highly compiler dependend. Maybe
 * the decode.c version for 'normal' processor may be faster
 * even for Intel processors.
 */

/* decode_i386.c*/

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "decode_i386.h"
#include "dct64_i386.h"
#include "tabinit.h"


/* old WRITE_SAMPLE */
/*
#define WRITE_SAMPLE(samples,sum,clip) \
  if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \
  else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \
  else { *(samples) = ((sum)>0 ? (sum)+0.5 : (sum)-0.5) ; }
*/
#define WRITE_SAMPLE(samples,sum,clip) *(samples) = (float)sum;  // sh0


  int synth_1to1_mono(PMPSTR mp, real *bandPtr,unsigned char *samples,int *pnt)
{
  float samples_tmp[64];
  float *tmp1 = samples_tmp;
  int i,ret;
  int pnt1 = 0;

  ret = synth_1to1(mp,bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
  samples += *pnt;  // char offset

  for(i=0;i<32;i++) {
    *( (float *) samples) = *tmp1;
    samples += 4; // char offset
    tmp1 += 2; // float offset (skip one)
  }
  *pnt += 64*2;  // chars

  return ret;
}

int synth_1to1(PMPSTR mp, real *bandPtr,int channel,unsigned char *out,int *pnt)
{
  static const int step = 2;
  int bo;
  float *samples = (float *) (out + *pnt);  // sh0

  real *b0,(*buf)[0x110];
  int clip = 0;
  int bo1;

  bo = mp->synth_bo;

  if(!channel) {
    bo--;
    bo &= 0xf;
    buf = mp->synth_buffs[0];
  }
  else {
    samples++;
    buf = mp->synth_buffs[1];
  }

  if(bo & 0x1) {
    b0 = buf[0];
    bo1 = bo;
	if (!(mp->quick_dirty)) {
	    dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr);
	}
  }
  else {
    b0 = buf[1];
    bo1 = bo+1;
	if (!(mp->quick_dirty)) {
	    dct64(buf[0]+bo,buf[1]+bo+1,bandPtr);
	}
  }

  mp->synth_bo = bo;

  {
    register int j;
    real *window = decwin + 16 - bo1;

    for (j=16;j;j--,b0+=0x10,window+=0x20,samples+=step)
    {
	if (!(mp->quick_dirty)) {
		real sum;
		sum  = window[0x0] * b0[0x0];
		sum -= window[0x1] * b0[0x1];
		sum += window[0x2] * b0[0x2];
		sum -= window[0x3] * b0[0x3];
		sum += window[0x4] * b0[0x4];
		sum -= window[0x5] * b0[0x5];
		sum += window[0x6] * b0[0x6];
		sum -= window[0x7] * b0[0x7];
		sum += window[0x8] * b0[0x8];
		sum -= window[0x9] * b0[0x9];
		sum += window[0xA] * b0[0xA];
		sum -= window[0xB] * b0[0xB];
		sum += window[0xC] * b0[0xC];
		sum -= window[0xD] * b0[0xD];
		sum += window[0xE] * b0[0xE];
		sum -= window[0xF] * b0[0xF];

		WRITE_SAMPLE(samples,sum,clip);
		}
    }

    {
      real sum;
      sum  = window[0x0] * b0[0x0];
      sum += window[0x2] * b0[0x2];
      sum += window[0x4] * b0[0x4];
      sum += window[0x6] * b0[0x6];
      sum += window[0x8] * b0[0x8];
      sum += window[0xA] * b0[0xA];
      sum += window[0xC] * b0[0xC];
      sum += window[0xE] * b0[0xE];
      WRITE_SAMPLE(samples,sum,clip);
      b0-=0x10,window-=0x20,samples+=step;
    }
    window += bo1<<1;

    for (j=15;j;j--,b0-=0x10,window-=0x20,samples+=step)
	{
	if (!(mp->quick_dirty)) {
		real sum;
		sum = -window[-0x1] * b0[0x0];
		sum -= window[-0x2] * b0[0x1];
		sum -= window[-0x3] * b0[0x2];
		sum -= window[-0x4] * b0[0x3];
		sum -= window[-0x5] * b0[0x4];
		sum -= window[-0x6] * b0[0x5];
		sum -= window[-0x7] * b0[0x6];
		sum -= window[-0x8] * b0[0x7];
		sum -= window[-0x9] * b0[0x8];
		sum -= window[-0xA] * b0[0x9];
		sum -= window[-0xB] * b0[0xA];
		sum -= window[-0xC] * b0[0xB];
		sum -= window[-0xD] * b0[0xC];
		sum -= window[-0xE] * b0[0xD];
		sum -= window[-0xF] * b0[0xE];
		sum -= window[-0x0] * b0[0xF];

		WRITE_SAMPLE(samples,sum,clip);
		}
    }
  }
  *pnt += 128*2; // sh0

  return clip;
}

