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1905 serge 1 
/*
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	dct64.c: DCT64, the plain C version
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	copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1
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	see COPYING and AUTHORS files in distribution or http://mpg123.org
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	initially written by Michael Hipp
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*/
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/*
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 * Discrete Cosine Tansform (DCT) for subband synthesis
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 *
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 * -funroll-loops (for gcc) will remove the loops for better performance
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 * using loops in the source-code enhances readabillity
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 *
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 *
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 * TODO: write an optimized version for the down-sampling modes
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 *       (in these modes the bands 16-31 (2:1) or 8-31 (4:1) are zero
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 */
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#include "mpg123lib_intern.h"
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void dct64(real *out0,real *out1,real *samples)
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{
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  real bufs[64];
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 {
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  register int i,j;
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  register real *b1,*b2,*bs,*costab;
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  b1 = samples;
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  bs = bufs;
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  costab = pnts[0]+16;
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  b2 = b1 + 32;
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  for(i=15;i>=0;i--)
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    *bs++ = (*b1++ + *--b2);
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  for(i=15;i>=0;i--)
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    *bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
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  b1 = bufs;
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  costab = pnts[1]+8;
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  b2 = b1 + 16;
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  {
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    for(i=7;i>=0;i--)
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      *bs++ = (*b1++ + *--b2);
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    for(i=7;i>=0;i--)
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      *bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
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    b2 += 32;
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    costab += 8;
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    for(i=7;i>=0;i--)
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      *bs++ = (*b1++ + *--b2);
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    for(i=7;i>=0;i--)
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      *bs++ = REAL_MUL((*b1++ - *--b2), *--costab);
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    b2 += 32;
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  }
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  bs = bufs;
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  costab = pnts[2];
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  b2 = b1 + 8;
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  for(j=2;j;j--)
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  {
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    for(i=3;i>=0;i--)
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      *bs++ = (*b1++ + *--b2);
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    for(i=3;i>=0;i--)
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      *bs++ = REAL_MUL((*--b2 - *b1++), costab[i]);
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    b2 += 16;
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    for(i=3;i>=0;i--)
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      *bs++ = (*b1++ + *--b2);
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    for(i=3;i>=0;i--)
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      *bs++ = REAL_MUL((*b1++ - *--b2), costab[i]);
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    b2 += 16;
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  }
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  b1 = bufs;
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  costab = pnts[3];
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  b2 = b1 + 4;
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  for(j=4;j;j--)
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  {
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    *bs++ = (*b1++ + *--b2);
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    *bs++ = (*b1++ + *--b2);
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    *bs++ = REAL_MUL((*--b2 - *b1++), costab[1]);
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    *bs++ = REAL_MUL((*--b2 - *b1++), costab[0]);
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    b2 += 8;
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    *bs++ = (*b1++ + *--b2);
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    *bs++ = (*b1++ + *--b2);
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    *bs++ = REAL_MUL((*b1++ - *--b2), costab[1]);
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    *bs++ = REAL_MUL((*b1++ - *--b2), costab[0]);
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    b2 += 8;
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  }
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  bs = bufs;
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  costab = pnts[4];
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  for(j=8;j;j--)
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  {
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    real v0,v1;
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    v0=*b1++; v1 = *b1++;
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    *bs++ = (v0 + v1);
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    *bs++ = REAL_MUL((v0 - v1), (*costab));
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    v0=*b1++; v1 = *b1++;
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    *bs++ = (v0 + v1);
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    *bs++ = REAL_MUL((v1 - v0), (*costab));
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  }
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107 
 }
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 {
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  register real *b1;
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  register int i;
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  for(b1=bufs,i=8;i;i--,b1+=4)
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    b1[2] += b1[3];
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  for(b1=bufs,i=4;i;i--,b1+=8)
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  {
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    b1[4] += b1[6];
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    b1[6] += b1[5];
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    b1[5] += b1[7];
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  }
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  for(b1=bufs,i=2;i;i--,b1+=16)
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  {
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    b1[8]  += b1[12];
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    b1[12] += b1[10];
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    b1[10] += b1[14];
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    b1[14] += b1[9];
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    b1[9]  += b1[13];
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    b1[13] += b1[11];
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    b1[11] += b1[15];
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  }
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 }
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  out0[0x10*16] = REAL_SCALE_DCT64(bufs[0]);
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  out0[0x10*15] = REAL_SCALE_DCT64(bufs[16+0]  + bufs[16+8]);
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  out0[0x10*14] = REAL_SCALE_DCT64(bufs[8]);
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  out0[0x10*13] = REAL_SCALE_DCT64(bufs[16+8]  + bufs[16+4]);
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  out0[0x10*12] = REAL_SCALE_DCT64(bufs[4]);
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  out0[0x10*11] = REAL_SCALE_DCT64(bufs[16+4]  + bufs[16+12]);
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  out0[0x10*10] = REAL_SCALE_DCT64(bufs[12]);
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  out0[0x10* 9] = REAL_SCALE_DCT64(bufs[16+12] + bufs[16+2]);
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  out0[0x10* 8] = REAL_SCALE_DCT64(bufs[2]);
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  out0[0x10* 7] = REAL_SCALE_DCT64(bufs[16+2]  + bufs[16+10]);
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  out0[0x10* 6] = REAL_SCALE_DCT64(bufs[10]);
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  out0[0x10* 5] = REAL_SCALE_DCT64(bufs[16+10] + bufs[16+6]);
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  out0[0x10* 4] = REAL_SCALE_DCT64(bufs[6]);
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  out0[0x10* 3] = REAL_SCALE_DCT64(bufs[16+6]  + bufs[16+14]);
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  out0[0x10* 2] = REAL_SCALE_DCT64(bufs[14]);
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  out0[0x10* 1] = REAL_SCALE_DCT64(bufs[16+14] + bufs[16+1]);
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  out0[0x10* 0] = REAL_SCALE_DCT64(bufs[1]);
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  out1[0x10* 0] = REAL_SCALE_DCT64(bufs[1]);
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  out1[0x10* 1] = REAL_SCALE_DCT64(bufs[16+1]  + bufs[16+9]);
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  out1[0x10* 2] = REAL_SCALE_DCT64(bufs[9]);
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  out1[0x10* 3] = REAL_SCALE_DCT64(bufs[16+9]  + bufs[16+5]);
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  out1[0x10* 4] = REAL_SCALE_DCT64(bufs[5]);
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  out1[0x10* 5] = REAL_SCALE_DCT64(bufs[16+5]  + bufs[16+13]);
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  out1[0x10* 6] = REAL_SCALE_DCT64(bufs[13]);
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  out1[0x10* 7] = REAL_SCALE_DCT64(bufs[16+13] + bufs[16+3]);
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  out1[0x10* 8] = REAL_SCALE_DCT64(bufs[3]);
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  out1[0x10* 9] = REAL_SCALE_DCT64(bufs[16+3]  + bufs[16+11]);
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  out1[0x10*10] = REAL_SCALE_DCT64(bufs[11]);
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  out1[0x10*11] = REAL_SCALE_DCT64(bufs[16+11] + bufs[16+7]);
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  out1[0x10*12] = REAL_SCALE_DCT64(bufs[7]);
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  out1[0x10*13] = REAL_SCALE_DCT64(bufs[16+7]  + bufs[16+15]);
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  out1[0x10*14] = REAL_SCALE_DCT64(bufs[15]);
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  out1[0x10*15] = REAL_SCALE_DCT64(bufs[16+15]);
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172 
}
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