/*
 * Discrete Cosine Tansform (DCT) for subband synthesis
 * optimized for machines with no auto-increment. 
 * The performance is highly compiler dependend. Maybe
 * the dct64.c version for 'normal' processor may be faster
 * even for Intel processors.
 */

#include "mpg123_sdlsound.h"

static void dct64_1(real *out0,real *out1,real *b1,real *b2,real *samples)
{

 {
  register real *costab = pnts[0];

  b1[0x00] = samples[0x00] + samples[0x1F];
  b1[0x1F] = (samples[0x00] - samples[0x1F]) * costab[0x0];

  b1[0x01] = samples[0x01] + samples[0x1E];
  b1[0x1E] = (samples[0x01] - samples[0x1E]) * costab[0x1];

  b1[0x02] = samples[0x02] + samples[0x1D];
  b1[0x1D] = (samples[0x02] - samples[0x1D]) * costab[0x2];

  b1[0x03] = samples[0x03] + samples[0x1C];
  b1[0x1C] = (samples[0x03] - samples[0x1C]) * costab[0x3];

  b1[0x04] = samples[0x04] + samples[0x1B];
  b1[0x1B] = (samples[0x04] - samples[0x1B]) * costab[0x4];

  b1[0x05] = samples[0x05] + samples[0x1A];
  b1[0x1A] = (samples[0x05] - samples[0x1A]) * costab[0x5];

  b1[0x06] = samples[0x06] + samples[0x19];
  b1[0x19] = (samples[0x06] - samples[0x19]) * costab[0x6];

  b1[0x07] = samples[0x07] + samples[0x18];
  b1[0x18] = (samples[0x07] - samples[0x18]) * costab[0x7];

  b1[0x08] = samples[0x08] + samples[0x17];
  b1[0x17] = (samples[0x08] - samples[0x17]) * costab[0x8];

  b1[0x09] = samples[0x09] + samples[0x16];
  b1[0x16] = (samples[0x09] - samples[0x16]) * costab[0x9];

  b1[0x0A] = samples[0x0A] + samples[0x15];
  b1[0x15] = (samples[0x0A] - samples[0x15]) * costab[0xA];

  b1[0x0B] = samples[0x0B] + samples[0x14];
  b1[0x14] = (samples[0x0B] - samples[0x14]) * costab[0xB];

  b1[0x0C] = samples[0x0C] + samples[0x13];
  b1[0x13] = (samples[0x0C] - samples[0x13]) * costab[0xC];

  b1[0x0D] = samples[0x0D] + samples[0x12];
  b1[0x12] = (samples[0x0D] - samples[0x12]) * costab[0xD];

  b1[0x0E] = samples[0x0E] + samples[0x11];
  b1[0x11] = (samples[0x0E] - samples[0x11]) * costab[0xE];

  b1[0x0F] = samples[0x0F] + samples[0x10];
  b1[0x10] = (samples[0x0F] - samples[0x10]) * costab[0xF];
 }


 {
  register real *costab = pnts[1];

  b2[0x00] = b1[0x00] + b1[0x0F]; 
  b2[0x0F] = (b1[0x00] - b1[0x0F]) * costab[0];
  b2[0x01] = b1[0x01] + b1[0x0E]; 
  b2[0x0E] = (b1[0x01] - b1[0x0E]) * costab[1];
  b2[0x02] = b1[0x02] + b1[0x0D]; 
  b2[0x0D] = (b1[0x02] - b1[0x0D]) * costab[2];
  b2[0x03] = b1[0x03] + b1[0x0C]; 
  b2[0x0C] = (b1[0x03] - b1[0x0C]) * costab[3];
  b2[0x04] = b1[0x04] + b1[0x0B]; 
  b2[0x0B] = (b1[0x04] - b1[0x0B]) * costab[4];
  b2[0x05] = b1[0x05] + b1[0x0A]; 
  b2[0x0A] = (b1[0x05] - b1[0x0A]) * costab[5];
  b2[0x06] = b1[0x06] + b1[0x09]; 
  b2[0x09] = (b1[0x06] - b1[0x09]) * costab[6];
  b2[0x07] = b1[0x07] + b1[0x08]; 
  b2[0x08] = (b1[0x07] - b1[0x08]) * costab[7];

  b2[0x10] = b1[0x10] + b1[0x1F];
  b2[0x1F] = (b1[0x1F] - b1[0x10]) * costab[0];
  b2[0x11] = b1[0x11] + b1[0x1E];
  b2[0x1E] = (b1[0x1E] - b1[0x11]) * costab[1];
  b2[0x12] = b1[0x12] + b1[0x1D];
  b2[0x1D] = (b1[0x1D] - b1[0x12]) * costab[2];
  b2[0x13] = b1[0x13] + b1[0x1C];
  b2[0x1C] = (b1[0x1C] - b1[0x13]) * costab[3];
  b2[0x14] = b1[0x14] + b1[0x1B];
  b2[0x1B] = (b1[0x1B] - b1[0x14]) * costab[4];
  b2[0x15] = b1[0x15] + b1[0x1A];
  b2[0x1A] = (b1[0x1A] - b1[0x15]) * costab[5];
  b2[0x16] = b1[0x16] + b1[0x19];
  b2[0x19] = (b1[0x19] - b1[0x16]) * costab[6];
  b2[0x17] = b1[0x17] + b1[0x18];
  b2[0x18] = (b1[0x18] - b1[0x17]) * costab[7];
 }

 {
  register real *costab = pnts[2];

  b1[0x00] = b2[0x00] + b2[0x07];
  b1[0x07] = (b2[0x00] - b2[0x07]) * costab[0];
  b1[0x01] = b2[0x01] + b2[0x06];
  b1[0x06] = (b2[0x01] - b2[0x06]) * costab[1];
  b1[0x02] = b2[0x02] + b2[0x05];
  b1[0x05] = (b2[0x02] - b2[0x05]) * costab[2];
  b1[0x03] = b2[0x03] + b2[0x04];
  b1[0x04] = (b2[0x03] - b2[0x04]) * costab[3];

  b1[0x08] = b2[0x08] + b2[0x0F];
  b1[0x0F] = (b2[0x0F] - b2[0x08]) * costab[0];
  b1[0x09] = b2[0x09] + b2[0x0E];
  b1[0x0E] = (b2[0x0E] - b2[0x09]) * costab[1];
  b1[0x0A] = b2[0x0A] + b2[0x0D];
  b1[0x0D] = (b2[0x0D] - b2[0x0A]) * costab[2];
  b1[0x0B] = b2[0x0B] + b2[0x0C];
  b1[0x0C] = (b2[0x0C] - b2[0x0B]) * costab[3];

  b1[0x10] = b2[0x10] + b2[0x17];
  b1[0x17] = (b2[0x10] - b2[0x17]) * costab[0];
  b1[0x11] = b2[0x11] + b2[0x16];
  b1[0x16] = (b2[0x11] - b2[0x16]) * costab[1];
  b1[0x12] = b2[0x12] + b2[0x15];
  b1[0x15] = (b2[0x12] - b2[0x15]) * costab[2];
  b1[0x13] = b2[0x13] + b2[0x14];
  b1[0x14] = (b2[0x13] - b2[0x14]) * costab[3];

  b1[0x18] = b2[0x18] + b2[0x1F];
  b1[0x1F] = (b2[0x1F] - b2[0x18]) * costab[0];
  b1[0x19] = b2[0x19] + b2[0x1E];
  b1[0x1E] = (b2[0x1E] - b2[0x19]) * costab[1];
  b1[0x1A] = b2[0x1A] + b2[0x1D];
  b1[0x1D] = (b2[0x1D] - b2[0x1A]) * costab[2];
  b1[0x1B] = b2[0x1B] + b2[0x1C];
  b1[0x1C] = (b2[0x1C] - b2[0x1B]) * costab[3];
 }

 {
  register real const cos0 = pnts[3][0];
  register real const cos1 = pnts[3][1];

  b2[0x00] = b1[0x00] + b1[0x03];
  b2[0x03] = (b1[0x00] - b1[0x03]) * cos0;
  b2[0x01] = b1[0x01] + b1[0x02];
  b2[0x02] = (b1[0x01] - b1[0x02]) * cos1;

  b2[0x04] = b1[0x04] + b1[0x07];
  b2[0x07] = (b1[0x07] - b1[0x04]) * cos0;
  b2[0x05] = b1[0x05] + b1[0x06];
  b2[0x06] = (b1[0x06] - b1[0x05]) * cos1;

  b2[0x08] = b1[0x08] + b1[0x0B];
  b2[0x0B] = (b1[0x08] - b1[0x0B]) * cos0;
  b2[0x09] = b1[0x09] + b1[0x0A];
  b2[0x0A] = (b1[0x09] - b1[0x0A]) * cos1;
  
  b2[0x0C] = b1[0x0C] + b1[0x0F];
  b2[0x0F] = (b1[0x0F] - b1[0x0C]) * cos0;
  b2[0x0D] = b1[0x0D] + b1[0x0E];
  b2[0x0E] = (b1[0x0E] - b1[0x0D]) * cos1;

  b2[0x10] = b1[0x10] + b1[0x13];
  b2[0x13] = (b1[0x10] - b1[0x13]) * cos0;
  b2[0x11] = b1[0x11] + b1[0x12];
  b2[0x12] = (b1[0x11] - b1[0x12]) * cos1;

  b2[0x14] = b1[0x14] + b1[0x17];
  b2[0x17] = (b1[0x17] - b1[0x14]) * cos0;
  b2[0x15] = b1[0x15] + b1[0x16];
  b2[0x16] = (b1[0x16] - b1[0x15]) * cos1;

  b2[0x18] = b1[0x18] + b1[0x1B];
  b2[0x1B] = (b1[0x18] - b1[0x1B]) * cos0;
  b2[0x19] = b1[0x19] + b1[0x1A];
  b2[0x1A] = (b1[0x19] - b1[0x1A]) * cos1;

  b2[0x1C] = b1[0x1C] + b1[0x1F];
  b2[0x1F] = (b1[0x1F] - b1[0x1C]) * cos0;
  b2[0x1D] = b1[0x1D] + b1[0x1E];
  b2[0x1E] = (b1[0x1E] - b1[0x1D]) * cos1;
 }

 {
  register real const cos0 = pnts[4][0];

  b1[0x00] = b2[0x00] + b2[0x01];
  b1[0x01] = (b2[0x00] - b2[0x01]) * cos0;
  b1[0x02] = b2[0x02] + b2[0x03];
  b1[0x03] = (b2[0x03] - b2[0x02]) * cos0;
  b1[0x02] += b1[0x03];

  b1[0x04] = b2[0x04] + b2[0x05];
  b1[0x05] = (b2[0x04] - b2[0x05]) * cos0;
  b1[0x06] = b2[0x06] + b2[0x07];
  b1[0x07] = (b2[0x07] - b2[0x06]) * cos0;
  b1[0x06] += b1[0x07];
  b1[0x04] += b1[0x06];
  b1[0x06] += b1[0x05];
  b1[0x05] += b1[0x07];

  b1[0x08] = b2[0x08] + b2[0x09];
  b1[0x09] = (b2[0x08] - b2[0x09]) * cos0;
  b1[0x0A] = b2[0x0A] + b2[0x0B];
  b1[0x0B] = (b2[0x0B] - b2[0x0A]) * cos0;
  b1[0x0A] += b1[0x0B];

  b1[0x0C] = b2[0x0C] + b2[0x0D];
  b1[0x0D] = (b2[0x0C] - b2[0x0D]) * cos0;
  b1[0x0E] = b2[0x0E] + b2[0x0F];
  b1[0x0F] = (b2[0x0F] - b2[0x0E]) * cos0;
  b1[0x0E] += b1[0x0F];
  b1[0x0C] += b1[0x0E];
  b1[0x0E] += b1[0x0D];
  b1[0x0D] += b1[0x0F];

  b1[0x10] = b2[0x10] + b2[0x11];
  b1[0x11] = (b2[0x10] - b2[0x11]) * cos0;
  b1[0x12] = b2[0x12] + b2[0x13];
  b1[0x13] = (b2[0x13] - b2[0x12]) * cos0;
  b1[0x12] += b1[0x13];

  b1[0x14] = b2[0x14] + b2[0x15];
  b1[0x15] = (b2[0x14] - b2[0x15]) * cos0;
  b1[0x16] = b2[0x16] + b2[0x17];
  b1[0x17] = (b2[0x17] - b2[0x16]) * cos0;
  b1[0x16] += b1[0x17];
  b1[0x14] += b1[0x16];
  b1[0x16] += b1[0x15];
  b1[0x15] += b1[0x17];

  b1[0x18] = b2[0x18] + b2[0x19];
  b1[0x19] = (b2[0x18] - b2[0x19]) * cos0;
  b1[0x1A] = b2[0x1A] + b2[0x1B];
  b1[0x1B] = (b2[0x1B] - b2[0x1A]) * cos0;
  b1[0x1A] += b1[0x1B];

  b1[0x1C] = b2[0x1C] + b2[0x1D];
  b1[0x1D] = (b2[0x1C] - b2[0x1D]) * cos0;
  b1[0x1E] = b2[0x1E] + b2[0x1F];
  b1[0x1F] = (b2[0x1F] - b2[0x1E]) * cos0;
  b1[0x1E] += b1[0x1F];
  b1[0x1C] += b1[0x1E];
  b1[0x1E] += b1[0x1D];
  b1[0x1D] += b1[0x1F];
 }

 out0[0x10*16] = b1[0x00];
 out0[0x10*12] = b1[0x04];
 out0[0x10* 8] = b1[0x02];
 out0[0x10* 4] = b1[0x06];
 out0[0x10* 0] = b1[0x01];
 out1[0x10* 0] = b1[0x01];
 out1[0x10* 4] = b1[0x05];
 out1[0x10* 8] = b1[0x03];
 out1[0x10*12] = b1[0x07];

 b1[0x08] += b1[0x0C];
 out0[0x10*14] = b1[0x08];
 b1[0x0C] += b1[0x0a];
 out0[0x10*10] = b1[0x0C];
 b1[0x0A] += b1[0x0E];
 out0[0x10* 6] = b1[0x0A];
 b1[0x0E] += b1[0x09];
 out0[0x10* 2] = b1[0x0E];
 b1[0x09] += b1[0x0D];
 out1[0x10* 2] = b1[0x09];
 b1[0x0D] += b1[0x0B];
 out1[0x10* 6] = b1[0x0D];
 b1[0x0B] += b1[0x0F];
 out1[0x10*10] = b1[0x0B];
 out1[0x10*14] = b1[0x0F];

 b1[0x18] += b1[0x1C];
 out0[0x10*15] = b1[0x10] + b1[0x18];
 out0[0x10*13] = b1[0x18] + b1[0x14];
 b1[0x1C] += b1[0x1a];
 out0[0x10*11] = b1[0x14] + b1[0x1C];
 out0[0x10* 9] = b1[0x1C] + b1[0x12];
 b1[0x1A] += b1[0x1E];
 out0[0x10* 7] = b1[0x12] + b1[0x1A];
 out0[0x10* 5] = b1[0x1A] + b1[0x16];
 b1[0x1E] += b1[0x19];
 out0[0x10* 3] = b1[0x16] + b1[0x1E];
 out0[0x10* 1] = b1[0x1E] + b1[0x11];
 b1[0x19] += b1[0x1D];
 out1[0x10* 1] = b1[0x11] + b1[0x19];
 out1[0x10* 3] = b1[0x19] + b1[0x15];
 b1[0x1D] += b1[0x1B];
 out1[0x10* 5] = b1[0x15] + b1[0x1D];
 out1[0x10* 7] = b1[0x1D] + b1[0x13];
 b1[0x1B] += b1[0x1F];
 out1[0x10* 9] = b1[0x13] + b1[0x1B];
 out1[0x10*11] = b1[0x1B] + b1[0x17];
 out1[0x10*13] = b1[0x17] + b1[0x1F];
 out1[0x10*15] = b1[0x1F];
}

/*
 * the call via dct64 is a trick to force GCC to use
 * (new) registers for the b1,b2 pointer to the bufs[xx] field
 */
void dct64(real *a,real *b,real *c)
{
  real bufs[0x40];
  dct64_1(a,b,bufs,bufs+0x20,c);
}