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rockbox/apps/codecs/Tremor/mdct.c
Tomasz Malesinski c13eba29ff FS #7833: Optimizations to the Vorbis codec: 
- ARM assembly version of parts of mdct,
- special case for vorbis_book_decodevv_add for 2 channels and even book->dim,
- store the output in vb->pcm if possible, as it is usually in IRAM as
  opposed to v->pcm.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14875 a1c6a512-1295-4272-9138-f99709370657
2007-09-27 21:58:51 +00:00

521 lines
15 KiB
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/********************************************************************
* *
* THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. *
* *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
* *
* THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002 *
* BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
* *
********************************************************************
function: normalized modified discrete cosine transform
power of two length transform only [64 <= n ]
last mod: $Id$
Original algorithm adapted long ago from _The use of multirate filter
banks for coding of high quality digital audio_, by T. Sporer,
K. Brandenburg and B. Edler, collection of the European Signal
Processing Conference (EUSIPCO), Amsterdam, June 1992, Vol.1, pp
211-214
The below code implements an algorithm that no longer looks much like
that presented in the paper, but the basic structure remains if you
dig deep enough to see it.
This module DOES NOT INCLUDE code to generate/apply the window
function. Everybody has their own weird favorite including me... I
happen to like the properties of y=sin(.5PI*sin^2(x)), but others may
vehemently disagree.
********************************************************************/
#include "ivorbiscodec.h"
#include "os.h"
#include "misc.h"
#include "mdct.h"
#include "mdct_lookup.h"
#ifdef CPU_ARM
extern void mdct_butterfly_32(DATA_TYPE *x);
extern void mdct_butterfly_generic_loop(DATA_TYPE *x1, DATA_TYPE *x2,
LOOKUP_T *T0, int step,
LOOKUP_T *Ttop);
STIN void mdct_butterfly_generic(DATA_TYPE *x,int points, int step){
mdct_butterfly_generic_loop(x + points, x + (points>>1),
sincos_lookup0, step, sincos_lookup0+1024);
}
#else
/* 8 point butterfly (in place) */
STIN void mdct_butterfly_8(DATA_TYPE *x){
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];
x[0] = r5 + r3;
x[1] = r7 - r1;
x[2] = r5 - r3;
x[3] = r7 + r1;
x[4] = r4 - r0;
x[5] = r6 - r2;
x[6] = r4 + r0;
x[7] = r6 + r2;
MB();
}
/* 16 point butterfly (in place, 4 register) */
STIN void mdct_butterfly_16(DATA_TYPE *x){
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);
MB();
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;
MB();
mdct_butterfly_8(x);
mdct_butterfly_8(x+8);
}
/* 32 point butterfly (in place, 4 register) */
STIN void mdct_butterfly_32(DATA_TYPE *x){
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);
MB();
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;
MB();
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] );
MB();
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] );
MB();
mdct_butterfly_16(x);
mdct_butterfly_16(x+16);
}
/* N/stage point generic N stage butterfly (in place, 4 register) */
void mdct_butterfly_generic(DATA_TYPE *x,int points, int step)
ICODE_ATTR_TREMOR_MDCT;
void mdct_butterfly_generic(DATA_TYPE *x,int points, int step){
LOOKUP_T *T = sincos_lookup0;
DATA_TYPE *x1 = x + points - 8;
DATA_TYPE *x2 = x + (points>>1) - 8;
REG_TYPE r0;
REG_TYPE r1;
REG_TYPE r2;
REG_TYPE r3;
do{
r0 = x1[6] - x2[6]; x1[6] += x2[6];
r1 = x2[7] - x1[7]; x1[7] += x2[7];
r2 = x1[4] - x2[4]; x1[4] += x2[4];
r3 = x2[5] - x1[5]; x1[5] += x2[5];
XPROD31( r1, r0, T[0], T[1], &x2[6], &x2[7] ); T+=step;
XPROD31( r3, r2, 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];
r2 = x1[0] - x2[0]; x1[0] += x2[0];
r3 = x2[1] - x1[1]; x1[1] += x2[1];
XPROD31( r1, r0, T[0], T[1], &x2[2], &x2[3] ); T+=step;
XPROD31( r3, r2, 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 = x1[7] - x2[7]; x1[7] += x2[7];
r2 = x1[4] - x2[4]; x1[4] += x2[4];
r3 = x1[5] - x2[5]; x1[5] += x2[5];
XNPROD31( r0, r1, T[0], T[1], &x2[6], &x2[7] ); T-=step;
XNPROD31( r2, r3, 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];
r2 = x1[0] - x2[0]; x1[0] += x2[0];
r3 = x1[1] - x2[1]; x1[1] += x2[1];
XNPROD31( r0, r1, T[0], T[1], &x2[2], &x2[3] ); T-=step;
XNPROD31( r2, r3, 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];
r2 = x2[4] - x1[4]; x1[4] += x2[4];
r3 = x2[5] - x1[5]; x1[5] += x2[5];
XPROD31( r0, r1, T[0], T[1], &x2[6], &x2[7] ); T+=step;
XPROD31( r2, r3, 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];
r2 = x2[0] - x1[0]; x1[0] += x2[0];
r3 = x2[1] - x1[1]; x1[1] += x2[1];
XPROD31( r0, r1, T[0], T[1], &x2[2], &x2[3] ); T+=step;
XPROD31( r2, r3, 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];
r2 = x1[4] - x2[4]; x1[4] += x2[4];
r3 = x2[5] - x1[5]; x1[5] += x2[5];
XNPROD31( r1, r0, T[0], T[1], &x2[6], &x2[7] ); T-=step;
XNPROD31( r3, r2, 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];
r2 = x1[0] - x2[0]; x1[0] += x2[0];
r3 = x2[1] - x1[1]; x1[1] += x2[1];
XNPROD31( r1, r0, T[0], T[1], &x2[2], &x2[3] ); T-=step;
XNPROD31( r3, r2, T[0], T[1], &x2[0], &x2[1] ); T-=step;
x1-=8; x2-=8;
}while(T>sincos_lookup0);
}
#endif /* CPU_ARM */
STIN void mdct_butterflies(DATA_TYPE *x,int points,int shift) {
int stages=8-shift;
int i,j;
for(i=0;--stages>0;i++){
for(j=0;j<(1<<i);j++)
mdct_butterfly_generic(x+(points>>i)*j,points>>i,4<<(i+shift));
}
for(j=0;j<points;j+=32)
mdct_butterfly_32(x+j);
}
static const unsigned char bitrev[16] ICONST_ATTR =
{0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15};
STIN int bitrev12(int x){
return bitrev[x>>8]|(bitrev[(x&0x0f0)>>4]<<4)|(((int)bitrev[x&0x00f])<<8);
}
STIN void mdct_bitreverse(DATA_TYPE *x,int n,int step,int shift) {
int bit = 0;
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;
REG_TYPE r2;
do{
REG_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;
w0[0] = r0 + r2;
w0[1] = r1 + r3;
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;
w1[0] = r0 - r2;
w1[1] = r3 - r1;
w0 += 4;
}while(T<Ttop);
do{
REG_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;
w0[0] = r0 + r2;
w0[1] = r1 + r3;
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;
w1[0] = r0 - r2;
w1[1] = r3 - r1;
w0 += 4;
}while(w0<w1);
}
void mdct_backward(int n, DATA_TYPE *in, DATA_TYPE *out)
ICODE_ATTR_TREMOR_MDCT;
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;
LOOKUP_T *T;
LOOKUP_T *V;
int shift;
int step;
for (shift=6;!(n&(1<<shift));shift++);
shift=13-shift;
step=2<<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;
do{
oX1-=4;
oX1[0]= iX[3];
oX1[1]= iX[2];
oX1[2]= iX[1];
oX1[3]= iX[0];
iX+=4;
}while(oX1>oX2);
}
}
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