dlls/winemp3.acm/decode_i386.c

   1 /*
   2  * Mpeg Layer-1,2,3 audio decoder
   3  * ------------------------------
   4  * copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved.
   5  * See also 'README'
   6  *
   7  * slighlty optimized for machines without autoincrement/decrement.
   8  * The performance is highly compiler dependend. Maybe
   9  * the decode.c version for 'normal' processor may be faster
  10  * even for Intel processors.
  11  *
  12  * This library is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Lesser General Public
  14  * License as published by the Free Software Foundation; either
  15  * version 2.1 of the License, or (at your option) any later version.
  16  *
  17  * This library is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * Lesser General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public
  23  * License along with this library; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  25  */
  26
  27 #include <stdlib.h>
  28 #include <math.h>
  29 #include <string.h>
  30
  31 #include "mpg123.h"
  32 #include "mpglib.h"
  33
  34 extern struct mpstr *gmp;
  35
  36  /* old WRITE_SAMPLE */
  37 #define WRITE_SAMPLE(samples,sum,clip) \
  38   if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \
  39   else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \
  40   else { *(samples) = sum; }
  41
  42 int synth_1to1_mono(real *bandPtr,unsigned char *samples,int *pnt)
  43 {
  44   short samples_tmp[64];
  45   short *tmp1 = samples_tmp;
  46   int i,ret;
  47   int pnt1 = 0;
  48
  49   ret = synth_1to1(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
  50   samples += *pnt;
  51
  52   for(i=0;i<32;i++) {
  53     *( (short *) samples) = *tmp1;
  54     samples += 2;
  55     tmp1 += 2;
  56   }
  57   *pnt += 64;
  58
  59   return ret;
  60 }
  61
  62
  63 int synth_1to1(real *bandPtr,int channel,unsigned char *out,int *pnt)
  64 {
  65   static const int step = 2;
  66   int bo;
  67   short *samples = (short *) (out + *pnt);
  68
  69   real *b0,(*buf)[0x110];
  70   int clip = 0;
  71   int bo1;
  72
  73   bo = gmp->synth_bo;
  74
  75   if(!channel) {
  76     bo--;
  77     bo &= 0xf;
  78     buf = gmp->synth_buffs[0];
  79   }
  80   else {
  81     samples++;
  82     buf = gmp->synth_buffs[1];
  83   }
  84
  85   if(bo & 0x1) {
  86     b0 = buf[0];
  87     bo1 = bo;
  88     dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr);
  89   }
  90   else {
  91     b0 = buf[1];
  92     bo1 = bo+1;
  93     dct64(buf[0]+bo,buf[1]+bo+1,bandPtr);
  94   }
  95
  96   gmp->synth_bo = bo;
  97
  98   {
  99     register int j;
 100     real *window = decwin + 16 - bo1;
 101
 102     for (j=16;j;j--,b0+=0x10,window+=0x20,samples+=step)
 103     {
 104       real sum;
 105       sum  = window[0x0] * b0[0x0];
 106       sum -= window[0x1] * b0[0x1];
 107       sum += window[0x2] * b0[0x2];
 108       sum -= window[0x3] * b0[0x3];
 109       sum += window[0x4] * b0[0x4];
 110       sum -= window[0x5] * b0[0x5];
 111       sum += window[0x6] * b0[0x6];
 112       sum -= window[0x7] * b0[0x7];
 113       sum += window[0x8] * b0[0x8];
 114       sum -= window[0x9] * b0[0x9];
 115       sum += window[0xA] * b0[0xA];
 116       sum -= window[0xB] * b0[0xB];
 117       sum += window[0xC] * b0[0xC];
 118       sum -= window[0xD] * b0[0xD];
 119       sum += window[0xE] * b0[0xE];
 120       sum -= window[0xF] * b0[0xF];
 121
 122       WRITE_SAMPLE(samples,sum,clip);
 123     }
 124
 125     {
 126       real sum;
 127       sum  = window[0x0] * b0[0x0];
 128       sum += window[0x2] * b0[0x2];
 129       sum += window[0x4] * b0[0x4];
 130       sum += window[0x6] * b0[0x6];
 131       sum += window[0x8] * b0[0x8];
 132       sum += window[0xA] * b0[0xA];
 133       sum += window[0xC] * b0[0xC];
 134       sum += window[0xE] * b0[0xE];
 135       WRITE_SAMPLE(samples,sum,clip);
 136       b0-=0x10,window-=0x20,samples+=step;
 137     }
 138     window += bo1<<1;
 139
 140     for (j=15;j;j--,b0-=0x10,window-=0x20,samples+=step)
 141     {
 142       real sum;
 143       sum = -window[-0x1] * b0[0x0];
 144       sum -= window[-0x2] * b0[0x1];
 145       sum -= window[-0x3] * b0[0x2];
 146       sum -= window[-0x4] * b0[0x3];
 147       sum -= window[-0x5] * b0[0x4];
 148       sum -= window[-0x6] * b0[0x5];
 149       sum -= window[-0x7] * b0[0x6];
 150       sum -= window[-0x8] * b0[0x7];
 151       sum -= window[-0x9] * b0[0x8];
 152       sum -= window[-0xA] * b0[0x9];
 153       sum -= window[-0xB] * b0[0xA];
 154       sum -= window[-0xC] * b0[0xB];
 155       sum -= window[-0xD] * b0[0xC];
 156       sum -= window[-0xE] * b0[0xD];
 157       sum -= window[-0xF] * b0[0xE];
 158       sum -= window[-0x0] * b0[0xF];
 159
 160       WRITE_SAMPLE(samples,sum,clip);
 161     }
 162   }
 163   *pnt += 128;
 164
 165   return clip;
 166 }