Tremolo (an ARM optimised version of the Tremor library for doing Ogg Vorbis decompression)
diff --git a/Tremolo/mdct.c b/Tremolo/mdct.c
new file mode 100644
index 0000000..450819b
--- /dev/null
+++ b/Tremolo/mdct.c
@@ -0,0 +1,562 @@
+/********************************************************************
+ * *
+ * 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 1994-2003 *
+ * 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: mdct.c,v 1.9.6.5 2003/04/29 04:03:27 xiphmont Exp $
+
+ 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"
+
+#include <stdio.h>
+
+#if defined(ONLY_C)
+STIN void presymmetry(DATA_TYPE *in,int n2,int step){
+ DATA_TYPE *aX;
+ DATA_TYPE *bX;
+ LOOKUP_T *T;
+ int n4=n2>>1;
+
+ aX = in+n2-3;
+ T = sincos_lookup0;
+
+ do{
+ REG_TYPE s0= aX[0];
+ REG_TYPE s2= aX[2];
+ XPROD31( s0, s2, T[0], T[1], &aX[0], &aX[2] ); T+=step;
+ aX-=4;
+ }while(aX>=in+n4);
+ do{
+ REG_TYPE s0= aX[0];
+ REG_TYPE s2= aX[2];
+ XPROD31( s0, s2, T[1], T[0], &aX[0], &aX[2] ); T-=step;
+ aX-=4;
+ }while(aX>=in);
+
+ aX = in+n2-4;
+ bX = in;
+ T = sincos_lookup0;
+ do{
+ REG_TYPE ri0= aX[0];
+ REG_TYPE ri2= aX[2];
+ REG_TYPE ro0= bX[0];
+ REG_TYPE ro2= bX[2];
+
+ XNPROD31( ro2, ro0, T[1], T[0], &aX[0], &aX[2] ); T+=step;
+ XNPROD31( ri2, ri0, T[0], T[1], &bX[0], &bX[2] );
+
+ aX-=4;
+ bX+=4;
+ }while(aX>=bX);
+}
+
+/* 8 point butterfly (in place) */
+STIN void mdct_butterfly_8(DATA_TYPE *x){
+
+ REG_TYPE s0 = x[0] + x[1];
+ REG_TYPE s1 = x[0] - x[1];
+ REG_TYPE s2 = x[2] + x[3];
+ REG_TYPE s3 = x[2] - x[3];
+ REG_TYPE s4 = x[4] + x[5];
+ REG_TYPE s5 = x[4] - x[5];
+ REG_TYPE s6 = x[6] + x[7];
+ REG_TYPE s7 = x[6] - x[7];
+
+ x[0] = s5 + s3;
+ x[1] = s7 - s1;
+ x[2] = s5 - s3;
+ x[3] = s7 + s1;
+ x[4] = s4 - s0;
+ x[5] = s6 - s2;
+ x[6] = s4 + s0;
+ x[7] = s6 + s2;
+ MB();
+}
+
+/* 16 point butterfly (in place, 4 register) */
+STIN void mdct_butterfly_16(DATA_TYPE *x){
+
+ REG_TYPE s0, s1, s2, s3;
+
+ s0 = x[ 8] - x[ 9]; x[ 8] += x[ 9];
+ s1 = x[10] - x[11]; x[10] += x[11];
+ s2 = x[ 1] - x[ 0]; x[ 9] = x[ 1] + x[0];
+ s3 = x[ 3] - x[ 2]; x[11] = x[ 3] + x[2];
+ x[ 0] = MULT31((s0 - s1) , cPI2_8);
+ x[ 1] = MULT31((s2 + s3) , cPI2_8);
+ x[ 2] = MULT31((s0 + s1) , cPI2_8);
+ x[ 3] = MULT31((s3 - s2) , cPI2_8);
+ MB();
+
+ s2 = x[12] - x[13]; x[12] += x[13];
+ s3 = x[14] - x[15]; x[14] += x[15];
+ s0 = x[ 4] - x[ 5]; x[13] = x[ 5] + x[ 4];
+ s1 = x[ 7] - x[ 6]; x[15] = x[ 7] + x[ 6];
+ x[ 4] = s2; x[ 5] = s1;
+ x[ 6] = s3; x[ 7] = s0;
+ 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 s0, s1, s2, s3;
+
+ s0 = x[16] - x[17]; x[16] += x[17];
+ s1 = x[18] - x[19]; x[18] += x[19];
+ s2 = x[ 1] - x[ 0]; x[17] = x[ 1] + x[ 0];
+ s3 = x[ 3] - x[ 2]; x[19] = x[ 3] + x[ 2];
+ XNPROD31( s0, s1, cPI3_8, cPI1_8, &x[ 0], &x[ 2] );
+ XPROD31 ( s2, s3, cPI1_8, cPI3_8, &x[ 1], &x[ 3] );
+ MB();
+
+ s0 = x[20] - x[21]; x[20] += x[21];
+ s1 = x[22] - x[23]; x[22] += x[23];
+ s2 = x[ 5] - x[ 4]; x[21] = x[ 5] + x[ 4];
+ s3 = x[ 7] - x[ 6]; x[23] = x[ 7] + x[ 6];
+ x[ 4] = MULT31((s0 - s1) , cPI2_8);
+ x[ 5] = MULT31((s3 + s2) , cPI2_8);
+ x[ 6] = MULT31((s0 + s1) , cPI2_8);
+ x[ 7] = MULT31((s3 - s2) , cPI2_8);
+ MB();
+
+ s0 = x[24] - x[25]; x[24] += x[25];
+ s1 = x[26] - x[27]; x[26] += x[27];
+ s2 = x[ 9] - x[ 8]; x[25] = x[ 9] + x[ 8];
+ s3 = x[11] - x[10]; x[27] = x[11] + x[10];
+ XNPROD31( s0, s1, cPI1_8, cPI3_8, &x[ 8], &x[10] );
+ XPROD31 ( s2, s3, cPI3_8, cPI1_8, &x[ 9], &x[11] );
+ MB();
+
+ s0 = x[28] - x[29]; x[28] += x[29];
+ s1 = x[30] - x[31]; x[30] += x[31];
+ s2 = x[12] - x[13]; x[29] = x[13] + x[12];
+ s3 = x[15] - x[14]; x[31] = x[15] + x[14];
+ x[12] = s0; x[13] = s3;
+ x[14] = s1; x[15] = s2;
+ MB();
+
+ mdct_butterfly_16(x);
+ mdct_butterfly_16(x+16);
+}
+
+/* N/stage point generic N stage butterfly (in place, 2 register) */
+STIN void mdct_butterfly_generic(DATA_TYPE *x,int points,int step){
+ LOOKUP_T *T = sincos_lookup0;
+ DATA_TYPE *x1 = x + points - 4;
+ DATA_TYPE *x2 = x + (points>>1) - 4;
+ REG_TYPE s0, s1, s2, s3;
+
+ do{
+ s0 = x1[0] - x1[1]; x1[0] += x1[1];
+ s1 = x1[3] - x1[2]; x1[2] += x1[3];
+ s2 = x2[1] - x2[0]; x1[1] = x2[1] + x2[0];
+ s3 = x2[3] - x2[2]; x1[3] = x2[3] + x2[2];
+ XPROD31( s1, s0, T[0], T[1], &x2[0], &x2[2] );
+ XPROD31( s2, s3, T[0], T[1], &x2[1], &x2[3] ); T+=step;
+ x1-=4;
+ x2-=4;
+ }while(T<sincos_lookup0+1024);
+ x1 = x + (points>>1) + (points>>2) - 4;
+ x2 = x + (points>>2) - 4;
+ T = sincos_lookup0+1024;
+ do{
+ s0 = x1[0] - x1[1]; x1[0] += x1[1];
+ s1 = x1[2] - x1[3]; x1[2] += x1[3];
+ s2 = x2[0] - x2[1]; x1[1] = x2[1] + x2[0];
+ s3 = x2[3] - x2[2]; x1[3] = x2[3] + x2[2];
+ XNPROD31( s0, s1, T[0], T[1], &x2[0], &x2[2] );
+ XNPROD31( s3, s2, T[0], T[1], &x2[1], &x2[3] ); T-=step;
+ x1-=4;
+ x2-=4;
+ }while(T>sincos_lookup0);
+}
+
+STIN void mdct_butterflies(DATA_TYPE *x,int points,int shift){
+
+ int stages=7-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 unsigned char bitrev[16]={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 shift){
+ int bit = 0;
+ DATA_TYPE *w = x+(n>>1);
+
+ do{
+ DATA_TYPE b = bitrev12(bit++);
+ DATA_TYPE *xx = x + (b>>shift);
+ REG_TYPE r;
+
+ w -= 2;
+
+ if(w>xx){
+
+ r = xx[0];
+ xx[0] = w[0];
+ w[0] = r;
+
+ r = xx[1];
+ xx[1] = w[1];
+ w[1] = r;
+ }
+ }while(w>x);
+}
+
+STIN void mdct_step7(DATA_TYPE *x,int n,int step){
+ DATA_TYPE *w0 = x;
+ DATA_TYPE *w1 = x+(n>>1);
+ LOOKUP_T *T = (step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1;
+ LOOKUP_T *Ttop = T+1024;
+ REG_TYPE s0, s1, s2, s3;
+
+ do{
+ w1 -= 2;
+
+ s0 = w0[0] + w1[0];
+ s1 = w1[1] - w0[1];
+ s2 = MULT32(s0, T[1]) + MULT32(s1, T[0]);
+ s3 = MULT32(s1, T[1]) - MULT32(s0, T[0]);
+ T+=step;
+
+ s0 = (w0[1] + w1[1])>>1;
+ s1 = (w0[0] - w1[0])>>1;
+ w0[0] = s0 + s2;
+ w0[1] = s1 + s3;
+ w1[0] = s0 - s2;
+ w1[1] = s3 - s1;
+
+ w0 += 2;
+ }while(T<Ttop);
+ do{
+ w1 -= 2;
+
+ s0 = w0[0] + w1[0];
+ s1 = w1[1] - w0[1];
+ T-=step;
+ s2 = MULT32(s0, T[0]) + MULT32(s1, T[1]);
+ s3 = MULT32(s1, T[0]) - MULT32(s0, T[1]);
+
+ s0 = (w0[1] + w1[1])>>1;
+ s1 = (w0[0] - w1[0])>>1;
+ w0[0] = s0 + s2;
+ w0[1] = s1 + s3;
+ w1[0] = s0 - s2;
+ w1[1] = s3 - s1;
+
+ w0 += 2;
+ }while(w0<w1);
+}
+#endif
+
+STIN void mdct_step8(DATA_TYPE *x, int n, int step){
+ LOOKUP_T *T;
+ LOOKUP_T *V;
+ DATA_TYPE *iX =x+(n>>1);
+
+ switch(step) {
+#if defined(ONLY_C)
+ default:
+ T=(step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1;
+ do{
+ REG_TYPE s0 = x[0];
+ REG_TYPE s1 = -x[1];
+ XPROD31( s0, s1, T[0], T[1], x, x+1); T+=step;
+ x +=2;
+ }while(x<iX);
+ break;
+#endif
+
+ case 1:
+ {
+ /* linear interpolation between table values: offset=0.5, step=1 */
+ REG_TYPE t0,t1,v0,v1,s0,s1;
+ T = sincos_lookup0;
+ V = sincos_lookup1;
+ t0 = (*T++)>>1;
+ t1 = (*T++)>>1;
+ do{
+ s0 = x[0];
+ s1 = -x[1];
+ t0 += (v0 = (*V++)>>1);
+ t1 += (v1 = (*V++)>>1);
+ XPROD31( s0, s1, t0, t1, x, x+1 );
+
+ s0 = x[2];
+ s1 = -x[3];
+ v0 += (t0 = (*T++)>>1);
+ v1 += (t1 = (*T++)>>1);
+ XPROD31( s0, s1, v0, v1, x+2, x+3 );
+
+ x += 4;
+ }while(x<iX);
+ break;
+ }
+
+ case 0:
+ {
+ /* linear interpolation between table values: offset=0.25, step=0.5 */
+ REG_TYPE t0,t1,v0,v1,q0,q1,s0,s1;
+ T = sincos_lookup0;
+ V = sincos_lookup1;
+ t0 = *T++;
+ t1 = *T++;
+ do{
+
+
+ v0 = *V++;
+ v1 = *V++;
+ t0 += (q0 = (v0-t0)>>2);
+ t1 += (q1 = (v1-t1)>>2);
+ s0 = x[0];
+ s1 = -x[1];
+ XPROD31( s0, s1, t0, t1, x, x+1 );
+ t0 = v0-q0;
+ t1 = v1-q1;
+ s0 = x[2];
+ s1 = -x[3];
+ XPROD31( s0, s1, t0, t1, x+2, x+3 );
+
+ t0 = *T++;
+ t1 = *T++;
+ v0 += (q0 = (t0-v0)>>2);
+ v1 += (q1 = (t1-v1)>>2);
+ s0 = x[4];
+ s1 = -x[5];
+ XPROD31( s0, s1, v0, v1, x+4, x+5 );
+ v0 = t0-q0;
+ v1 = t1-q1;
+ s0 = x[6];
+ s1 = -x[7];
+ XPROD31( s0, s1, v0, v1, x+5, x+6 );
+
+ x+=8;
+ }while(x<iX);
+ break;
+ }
+ }
+}
+
+extern int mdct_backwardARM(int n, DATA_TYPE *in);
+
+/* partial; doesn't perform last-step deinterleave/unrolling. That
+ can be done more efficiently during pcm output */
+void mdct_backward(int n, DATA_TYPE *in){
+ int step;
+
+#if defined(ONLY_C)
+ int shift;
+
+ for (shift=4;!(n&(1<<shift));shift++);
+ shift=13-shift;
+ step=2<<shift;
+
+ presymmetry(in,n>>1,step);
+ mdct_butterflies(in,n>>1,shift);
+ mdct_bitreverse(in,n,shift);
+ mdct_step7(in,n,step);
+ mdct_step8(in,n,step>>2);
+#else
+ step = mdct_backwardARM(n, in);
+ if (step < 1)
+ mdct_step8(in,n,step);
+#endif
+}
+
+#if defined(ONLY_C)
+void mdct_shift_right(int n, DATA_TYPE *in, DATA_TYPE *right){
+ int i;
+ n>>=2;
+ in+=1;
+
+ for(i=0;i<n;i++)
+ right[i]=in[i<<1];
+}
+#endif
+
+extern ogg_int16_t *mdct_unroll_prelap(ogg_int16_t *out,
+ DATA_TYPE *post,
+ DATA_TYPE *l,
+ int step);
+extern ogg_int16_t *mdct_unroll_part2(ogg_int16_t *out,
+ DATA_TYPE *post,
+ DATA_TYPE *l,
+ DATA_TYPE *r,
+ int step,
+ LOOKUP_T *wL,
+ LOOKUP_T *wR);
+extern ogg_int16_t *mdct_unroll_part3(ogg_int16_t *out,
+ DATA_TYPE *post,
+ DATA_TYPE *l,
+ DATA_TYPE *r,
+ int step,
+ LOOKUP_T *wL,
+ LOOKUP_T *wR);
+extern ogg_int16_t *mdct_unroll_postlap(ogg_int16_t *out,
+ DATA_TYPE *post,
+ DATA_TYPE *l,
+ int step);
+
+void mdct_unroll_lap(int n0,int n1,
+ int lW,int W,
+ DATA_TYPE *in,
+ DATA_TYPE *right,
+ LOOKUP_T *w0,
+ LOOKUP_T *w1,
+ ogg_int16_t *out,
+ int step,
+ int start, /* samples, this frame */
+ int end /* samples, this frame */){
+
+ DATA_TYPE *l=in+(W&&lW ? n1>>1 : n0>>1);
+ DATA_TYPE *r=right+(lW ? n1>>2 : n0>>2);
+ DATA_TYPE *post;
+ LOOKUP_T *wR=(W && lW ? w1+(n1>>1) : w0+(n0>>1));
+ LOOKUP_T *wL=(W && lW ? w1 : w0 );
+
+ int preLap=(lW && !W ? (n1>>2)-(n0>>2) : 0 );
+ int halfLap=(lW && W ? (n1>>2) : (n0>>2) );
+ int postLap=(!lW && W ? (n1>>2)-(n0>>2) : 0 );
+ int n,off;
+
+ /* preceeding direct-copy lapping from previous frame, if any */
+ if(preLap){
+ n = (end<preLap?end:preLap);
+ off = (start<preLap?start:preLap);
+ post = r-n;
+ r -= off;
+ start -= off;
+ end -= n;
+#if defined(ONLY_C)
+ while(r>post){
+ *out = CLIP_TO_15((*--r)>>9);
+ out+=step;
+ }
+#else
+ out = mdct_unroll_prelap(out,post,r,step);
+ n -= off;
+ if (n < 0)
+ n = 0;
+ r -= n;
+#endif
+ }
+
+ /* cross-lap; two halves due to wrap-around */
+ n = (end<halfLap?end:halfLap);
+ off = (start<halfLap?start:halfLap);
+ post = r-n;
+ r -= off;
+ l -= off*2;
+ start -= off;
+ wR -= off;
+ wL += off;
+ end -= n;
+#if defined(ONLY_C)
+ while(r>post){
+ l-=2;
+ *out = CLIP_TO_15((MULT31(*--r,*--wR) + MULT31(*l,*wL++))>>9);
+ out+=step;
+ }
+#else
+ out = mdct_unroll_part2(out, post, l, r, step, wL, wR);
+ n -= off;
+ if (n < 0)
+ n = 0;
+ l -= 2*n;
+ r -= n;
+ wR -= n;
+ wL += n;
+#endif
+
+ n = (end<halfLap?end:halfLap);
+ off = (start<halfLap?start:halfLap);
+ post = r+n;
+ r += off;
+ l += off*2;
+ start -= off;
+ end -= n;
+ wR -= off;
+ wL += off;
+#if defined(ONLY_C)
+ while(r<post){
+ *out = CLIP_TO_15((MULT31(*r++,*--wR) - MULT31(*l,*wL++))>>9);
+ out+=step;
+ l+=2;
+ }
+#else
+ out = mdct_unroll_part3(out, post, l, r, step, wL, wR);
+ n -= off;
+ if (n < 0)
+ n = 0;
+ l += 2*n;
+ r += n;
+ wR -= n;
+ wL += n;
+#endif
+
+ /* preceeding direct-copy lapping from previous frame, if any */
+ if(postLap){
+ n = (end<postLap?end:postLap);
+ off = (start<postLap?start:postLap);
+ post = l+n*2;
+ l += off*2;
+#if defined(ONLY_C)
+ while(l<post){
+ *out = CLIP_TO_15((-*l)>>9);
+ out+=step;
+ l+=2;
+ }
+#else
+ out = mdct_unroll_postlap(out,post,l,step);
+#endif
+ }
+}
+