* THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *

 last mod: $Id: mdct.c,v 1.9 2002/10/16 09:17:39 xiphmont Exp $

#include "codebook.h"

  REG_TYPE r0   = x[4] + x[0];

  REG_TYPE r1   = x[4] - x[0];

  REG_TYPE r2   = x[5] + x[1];

  REG_TYPE r3   = x[5] - x[1];

  REG_TYPE r4   = x[6] + x[2];

  REG_TYPE r5   = x[6] - x[2];

  REG_TYPE r6   = x[7] + x[3];

  REG_TYPE r7   = x[7] - x[3];

  REG_TYPE r0, r1;

	   r0 = x[ 0] - x[ 8]; x[ 8] += x[ 0];

	   r1 = x[ 1] - x[ 9]; x[ 9] += x[ 1];

	   x[ 0] = MULT31((r0 + r1) , cPI2_8);

	   x[ 1] = MULT31((r1 - r0) , cPI2_8);

	   r0 = x[10] - x[ 2]; x[10] += x[ 2];

	   r1 = x[ 3] - x[11]; x[11] += x[ 3];

	   x[ 2] = r1; x[ 3] = r0;

	   MB();

	   r0 = x[12] - x[ 4]; x[12] += x[ 4];

	   r1 = x[13] - x[ 5]; x[13] += x[ 5];

	   x[ 4] = MULT31((r0 - r1) , cPI2_8);

	   x[ 5] = MULT31((r0 + r1) , cPI2_8);

	   MB();

	   r0 = x[14] - x[ 6]; x[14] += x[ 6];

	   r1 = x[15] - x[ 7]; x[15] += x[ 7];

	   x[ 6] = r0; x[ 7] = r1;

  REG_TYPE r0, r1;

	   r0 = x[30] - x[14]; x[30] += x[14];           

	   r1 = x[31] - x[15]; x[31] += x[15];

	   x[14] = r0; x[15] = r1;

	   MB();

	   r0 = x[28] - x[12]; x[28] += x[12];           

	   r1 = x[29] - x[13]; x[29] += x[13];

	   XNPROD31( r0, r1, cPI1_8, cPI3_8, &x[12], &x[13] );

	   MB();

	   r0 = x[26] - x[10]; x[26] += x[10];

	   r1 = x[27] - x[11]; x[27] += x[11];

	   x[10] = MULT31((r0 - r1) , cPI2_8);

	   x[11] = MULT31((r0 + r1) , cPI2_8);

	   r0 = x[24] - x[ 8]; x[24] += x[ 8];

	   r1 = x[25] - x[ 9]; x[25] += x[ 9];

	   XNPROD31( r0, r1, cPI3_8, cPI1_8, &x[ 8], &x[ 9] );

	   MB();

	   r0 = x[22] - x[ 6]; x[22] += x[ 6];

	   r1 = x[ 7] - x[23]; x[23] += x[ 7];

	   x[ 6] = r1; x[ 7] = r0;

	   r0 = x[ 4] - x[20]; x[20] += x[ 4];

	   r1 = x[ 5] - x[21]; x[21] += x[ 5];

	   XPROD31 ( r0, r1, cPI3_8, cPI1_8, &x[ 4], &x[ 5] );

	   r0 = x[ 2] - x[18]; x[18] += x[ 2];

	   r1 = x[ 3] - x[19]; x[19] += x[ 3];

	   x[ 2] = MULT31((r1 + r0) , cPI2_8);

	   x[ 3] = MULT31((r1 - r0) , cPI2_8);

	   MB();

	   r0 = x[ 0] - x[16]; x[16] += x[ 0];

	   r1 = x[ 1] - x[17]; x[17] += x[ 1];

	   XPROD31 ( r0, r1, cPI1_8, cPI3_8, &x[ 0], &x[ 1] );

  LOOKUP_T *T   = sincos_lookup0;

  DATA_TYPE *x1        = x + points      - 8;

  DATA_TYPE *x2        = x + (points>>1) - 8;

  REG_TYPE   r0;

  REG_TYPE   r1;

    r0 = x1[6] - x2[6]; x1[6] += x2[6];

    r1 = x2[7] - x1[7]; x1[7] += x2[7];

    XPROD31( r1, r0, T[0], T[1], &x2[6], &x2[7] ); T+=step;

    r0 = x1[4] - x2[4]; x1[4] += x2[4];

    r1 = x2[5] - x1[5]; x1[5] += x2[5];

    XPROD31( r1, r0, T[0], T[1], &x2[4], &x2[5] ); T+=step;

    r0 = x1[2] - x2[2]; x1[2] += x2[2];

    r1 = x2[3] - x1[3]; x1[3] += x2[3];

    XPROD31( r1, r0, T[0], T[1], &x2[2], &x2[3] ); T+=step;

    r0 = x1[0] - x2[0]; x1[0] += x2[0];

    r1 = x2[1] - x1[1]; x1[1] += x2[1];

    XPROD31( r1, r0, T[0], T[1], &x2[0], &x2[1] ); T+=step;

    x1-=8; x2-=8;

    r0 = x1[6] - x2[6]; x1[6] += x2[6];

    r1 = x1[7] - x2[7]; x1[7] += x2[7];

    XNPROD31( r0, r1, T[0], T[1], &x2[6], &x2[7] ); T-=step;

    r0 = x1[4] - x2[4]; x1[4] += x2[4];

    r1 = x1[5] - x2[5]; x1[5] += x2[5];

    XNPROD31( r0, r1, T[0], T[1], &x2[4], &x2[5] ); T-=step;

    r0 = x1[2] - x2[2]; x1[2] += x2[2];

    r1 = x1[3] - x2[3]; x1[3] += x2[3];

    XNPROD31( r0, r1, T[0], T[1], &x2[2], &x2[3] ); T-=step;

    r0 = x1[0] - x2[0]; x1[0] += x2[0];

    r1 = x1[1] - x2[1]; x1[1] += x2[1];

    XNPROD31( r0, r1, T[0], T[1], &x2[0], &x2[1] ); T-=step;

    x1-=8; x2-=8;

  }while(T>sincos_lookup0);

  do{

    r0 = x2[6] - x1[6]; x1[6] += x2[6];

    r1 = x2[7] - x1[7]; x1[7] += x2[7];

    XPROD31( r0, r1, T[0], T[1], &x2[6], &x2[7] ); T+=step;

    r0 = x2[4] - x1[4]; x1[4] += x2[4];

    r1 = x2[5] - x1[5]; x1[5] += x2[5];

    XPROD31( r0, r1, T[0], T[1], &x2[4], &x2[5] ); T+=step;

    r0 = x2[2] - x1[2]; x1[2] += x2[2];

    r1 = x2[3] - x1[3]; x1[3] += x2[3];

    XPROD31( r0, r1, T[0], T[1], &x2[2], &x2[3] ); T+=step;

    r0 = x2[0] - x1[0]; x1[0] += x2[0];

    r1 = x2[1] - x1[1]; x1[1] += x2[1];

    XPROD31( r0, r1, T[0], T[1], &x2[0], &x2[1] ); T+=step;

    x1-=8; x2-=8;

  }while(T<sincos_lookup0+1024);

  do{

    r0 = x1[6] - x2[6]; x1[6] += x2[6];

    r1 = x2[7] - x1[7]; x1[7] += x2[7];

    XNPROD31( r1, r0, T[0], T[1], &x2[6], &x2[7] ); T-=step;

    r0 = x1[4] - x2[4]; x1[4] += x2[4];

    r1 = x2[5] - x1[5]; x1[5] += x2[5];

    XNPROD31( r1, r0, T[0], T[1], &x2[4], &x2[5] ); T-=step;

    r0 = x1[2] - x2[2]; x1[2] += x2[2];

    r1 = x2[3] - x1[3]; x1[3] += x2[3];

    XNPROD31( r1, r0, T[0], T[1], &x2[2], &x2[3] ); T-=step;

    r0 = x1[0] - x2[0]; x1[0] += x2[0];

    r1 = x2[1] - x1[1]; x1[1] += x2[1];

    XNPROD31( r1, r0, T[0], T[1], &x2[0], &x2[1] ); T-=step;

    x1-=8; x2-=8;

STIN void mdct_bitreverse(DATA_TYPE *x,int n,int step,int shift){

  DATA_TYPE   *w0    = x;

  DATA_TYPE   *w1    = x = w0+(n>>1);

  LOOKUP_T    *T = (step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1;

  LOOKUP_T    *Ttop  = T+1024;

  DATA_TYPE    r2;

    DATA_TYPE r3     = bitrev12(bit++);

    DATA_TYPE *x0    = x + ((r3 ^ 0xfff)>>shift) -1;

    DATA_TYPE *x1    = x + (r3>>shift);

    REG_TYPE  r0     = x0[0]  + x1[0];

    REG_TYPE  r1     = x1[1]  - x0[1];

	      XPROD32( r0, r1, T[1], T[0], &r2, &r3 ); T+=step;

	      w1    -= 4;

	      r0     = (x0[1] + x1[1])>>1;

              r1     = (x0[0] - x1[0])>>1;

	      w1[2]  = r0     - r2;

	      w1[3]  = r3     - r1;

	      r3     = bitrev12(bit++);

              x0     = x + ((r3 ^ 0xfff)>>shift) -1;

              x1     = x + (r3>>shift);

              r0     = x0[0]  + x1[0];

              r1     = x1[1]  - x0[1];

	      XPROD32( r0, r1, T[1], T[0], &r2, &r3 ); T+=step;

              r0     = (x0[1] + x1[1])>>1;

              r1     = (x0[0] - x1[0])>>1;

	      w0[2]  = r0     + r2;

	      w0[3]  = r1     + r3;

	      w0    += 4;

    DATA_TYPE r3     = bitrev12(bit++);

    DATA_TYPE *x0    = x + ((r3 ^ 0xfff)>>shift) -1;

    DATA_TYPE *x1    = x + (r3>>shift);

    REG_TYPE  r0     = x0[0]  + x1[0];

    REG_TYPE  r1     = x1[1]  - x0[1];

	      T-=step; XPROD32( r0, r1, T[0], T[1], &r2, &r3 );

	      w1    -= 4;

	      r0     = (x0[1] + x1[1])>>1;

              r1     = (x0[0] - x1[0])>>1;

	      w1[2]  = r0     - r2;

	      w1[3]  = r3     - r1;

	      r3     = bitrev12(bit++);

              x0     = x + ((r3 ^ 0xfff)>>shift) -1;

              x1     = x + (r3>>shift);

              r0     = x0[0]  + x1[0];

              r1     = x1[1]  - x0[1];

	      T-=step; XPROD32( r0, r1, T[0], T[1], &r2, &r3 );

              r0     = (x0[1] + x1[1])>>1;

              r1     = (x0[0] - x1[0])>>1;

	      w0[2]  = r0     + r2;

	      w0[3]  = r1     + r3;

	      w0    += 4;

void mdct_backward(int n, DATA_TYPE *in, DATA_TYPE *out){

  int n2=n>>1;

  int n4=n>>2;

  DATA_TYPE *iX;

  DATA_TYPE *oX;

  for (shift=6;!(n&(1<<shift));shift++);

  /* rotate */

  iX            = in+n2-7;

  oX            = out+n2+n4;

  T             = sincos_lookup0;

  do{

    oX-=4;

    XPROD31( iX[4], iX[6], T[0], T[1], &oX[2], &oX[3] ); T+=step;

    XPROD31( iX[0], iX[2], T[0], T[1], &oX[0], &oX[1] ); T+=step;

    iX-=8;

  }while(iX>=in+n4);

  do{

    oX-=4;

    XPROD31( iX[4], iX[6], T[1], T[0], &oX[2], &oX[3] ); T-=step;

    XPROD31( iX[0], iX[2], T[1], T[0], &oX[0], &oX[1] ); T-=step;

    iX-=8;

  }while(iX>=in);

  iX            = in+n2-8;

  oX            = out+n2+n4;

  T             = sincos_lookup0;

  do{

    T+=step; XNPROD31( iX[6], iX[4], T[0], T[1], &oX[0], &oX[1] );

    T+=step; XNPROD31( iX[2], iX[0], T[0], T[1], &oX[2], &oX[3] );

    iX-=8;

    oX+=4;

  }while(iX>=in+n4);

  do{

    T-=step; XNPROD31( iX[6], iX[4], T[1], T[0], &oX[0], &oX[1] );

    T-=step; XNPROD31( iX[2], iX[0], T[1], T[0], &oX[2], &oX[3] );

    iX-=8;

    oX+=4;

  }while(iX>=in);

  mdct_butterflies(out+n2,n2,shift);

  mdct_bitreverse(out,n,step,shift);

  /* rotate + window */

  step>>=2;

  {

    DATA_TYPE *oX1=out+n2+n4;

    DATA_TYPE *oX2=out+n2+n4;

    DATA_TYPE *iX =out;

    switch(step) {

      default: {

        T=(step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1;

        do{

          oX1-=4;

	  XPROD31( iX[0], -iX[1], T[0], T[1], &oX1[3], &oX2[0] ); T+=step;

	  XPROD31( iX[2], -iX[3], T[0], T[1], &oX1[2], &oX2[1] ); T+=step;

	  XPROD31( iX[4], -iX[5], T[0], T[1], &oX1[1], &oX2[2] ); T+=step;

	  XPROD31( iX[6], -iX[7], T[0], T[1], &oX1[0], &oX2[3] ); T+=step;

	  oX2+=4;

	  iX+=8;

	}while(iX<oX1);

	break;

      }

      case 1: {

        /* linear interpolation between table values: offset=0.5, step=1 */

	REG_TYPE  t0,t1,v0,v1;

        T         = sincos_lookup0;

        V         = sincos_lookup1;

	t0        = (*T++)>>1;

	t1        = (*T++)>>1;

        do{

          oX1-=4;

	  t0 += (v0 = (*V++)>>1);

	  t1 += (v1 = (*V++)>>1);

	  XPROD31( iX[0], -iX[1], t0, t1, &oX1[3], &oX2[0] );

	  v0 += (t0 = (*T++)>>1);

	  v1 += (t1 = (*T++)>>1);

	  XPROD31( iX[2], -iX[3], v0, v1, &oX1[2], &oX2[1] );

	  t0 += (v0 = (*V++)>>1);

	  t1 += (v1 = (*V++)>>1);

	  XPROD31( iX[4], -iX[5], t0, t1, &oX1[1], &oX2[2] );

	  v0 += (t0 = (*T++)>>1);

	  v1 += (t1 = (*T++)>>1);

	  XPROD31( iX[6], -iX[7], v0, v1, &oX1[0], &oX2[3] );

	  oX2+=4;

	  iX+=8;

	}while(iX<oX1);

	break;

      }

      case 0: {

        /* linear interpolation between table values: offset=0.25, step=0.5 */

	REG_TYPE  t0,t1,v0,v1,q0,q1;

        T         = sincos_lookup0;

        V         = sincos_lookup1;

	t0        = *T++;

	t1        = *T++;

        do{

          oX1-=4;

	  v0  = *V++;

	  v1  = *V++;

	  t0 +=  (q0 = (v0-t0)>>2);

	  t1 +=  (q1 = (v1-t1)>>2);

	  XPROD31( iX[0], -iX[1], t0, t1, &oX1[3], &oX2[0] );

	  t0  = v0-q0;

	  t1  = v1-q1;

	  XPROD31( iX[2], -iX[3], t0, t1, &oX1[2], &oX2[1] );

	  t0  = *T++;

	  t1  = *T++;

	  v0 += (q0 = (t0-v0)>>2);

	  v1 += (q1 = (t1-v1)>>2);

	  XPROD31( iX[4], -iX[5], v0, v1, &oX1[1], &oX2[2] );

	  v0  = t0-q0;

	  v1  = t1-q1;

	  XPROD31( iX[6], -iX[7], v0, v1, &oX1[0], &oX2[3] );

	  oX2+=4;

	  iX+=8;

	}while(iX<oX1);

	break;

      }

    iX=out+n2+n4;

    oX1=out+n4;

    oX2=oX1;

    do{

      oX1-=4;

      iX-=4;

      oX2[0] = -(oX1[3] = iX[3]);

      oX2[1] = -(oX1[2] = iX[2]);

      oX2[2] = -(oX1[1] = iX[1]);

      oX2[3] = -(oX1[0] = iX[0]);

      oX2+=4;

    }while(oX2<iX);

    iX=out+n2+n4;

    oX1=out+n2+n4;

    oX2=out+n2;