176 lines
4.4 KiB
C
176 lines
4.4 KiB
C
/*
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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;
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register const real *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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}
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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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}
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