246 lines
6.6 KiB
C
246 lines
6.6 KiB
C
/*
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* FFT/IFFT transforms
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* AltiVec-enabled
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* Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>
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* Based on code Copyright (c) 2002 Fabrice Bellard.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "../dsputil.h"
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#include "dsputil_altivec.h"
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/*
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those three macros are from libavcodec/fft.c
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and are required for the reference C code
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*/
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/* butter fly op */
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#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
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{\
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FFTSample ax, ay, bx, by;\
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bx=pre1;\
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by=pim1;\
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ax=qre1;\
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ay=qim1;\
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pre = (bx + ax);\
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pim = (by + ay);\
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qre = (bx - ax);\
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qim = (by - ay);\
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}
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#define MUL16(a,b) ((a) * (b))
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#define CMUL(pre, pim, are, aim, bre, bim) \
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{\
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pre = (MUL16(are, bre) - MUL16(aim, bim));\
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pim = (MUL16(are, bim) + MUL16(bre, aim));\
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}
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/**
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* Do a complex FFT with the parameters defined in fft_init(). The
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* input data must be permuted before with s->revtab table. No
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* 1.0/sqrt(n) normalization is done.
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* AltiVec-enabled
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* This code assumes that the 'z' pointer is 16 bytes-aligned
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* It also assumes all FFTComplex are 8 bytes-aligned pair of float
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* The code is exactly the same as the SSE version, except
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* that successive MUL + ADD/SUB have been merged into
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* fused multiply-add ('vec_madd' in altivec)
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*/
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void fft_calc_altivec(FFTContext *s, FFTComplex *z)
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{
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POWERPC_TBL_DECLARE(altivec_fft_num, s->nbits >= 6);
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#ifdef ALTIVEC_USE_REFERENCE_C_CODE
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int ln = s->nbits;
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int j, np, np2;
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int nblocks, nloops;
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register FFTComplex *p, *q;
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FFTComplex *exptab = s->exptab;
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int l;
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FFTSample tmp_re, tmp_im;
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POWERPC_TBL_START_COUNT(altivec_fft_num, s->nbits >= 6);
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np = 1 << ln;
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/* pass 0 */
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p=&z[0];
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j=(np >> 1);
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do {
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BF(p[0].re, p[0].im, p[1].re, p[1].im,
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p[0].re, p[0].im, p[1].re, p[1].im);
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p+=2;
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} while (--j != 0);
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/* pass 1 */
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p=&z[0];
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j=np >> 2;
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if (s->inverse) {
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do {
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BF(p[0].re, p[0].im, p[2].re, p[2].im,
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p[0].re, p[0].im, p[2].re, p[2].im);
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BF(p[1].re, p[1].im, p[3].re, p[3].im,
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p[1].re, p[1].im, -p[3].im, p[3].re);
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p+=4;
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} while (--j != 0);
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} else {
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do {
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BF(p[0].re, p[0].im, p[2].re, p[2].im,
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p[0].re, p[0].im, p[2].re, p[2].im);
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BF(p[1].re, p[1].im, p[3].re, p[3].im,
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p[1].re, p[1].im, p[3].im, -p[3].re);
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p+=4;
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} while (--j != 0);
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}
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/* pass 2 .. ln-1 */
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nblocks = np >> 3;
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nloops = 1 << 2;
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np2 = np >> 1;
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do {
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p = z;
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q = z + nloops;
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for (j = 0; j < nblocks; ++j) {
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BF(p->re, p->im, q->re, q->im,
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p->re, p->im, q->re, q->im);
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p++;
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q++;
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for(l = nblocks; l < np2; l += nblocks) {
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CMUL(tmp_re, tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
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BF(p->re, p->im, q->re, q->im,
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p->re, p->im, tmp_re, tmp_im);
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p++;
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q++;
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}
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p += nloops;
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q += nloops;
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}
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nblocks = nblocks >> 1;
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nloops = nloops << 1;
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} while (nblocks != 0);
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POWERPC_TBL_STOP_COUNT(altivec_fft_num, s->nbits >= 6);
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#else /* ALTIVEC_USE_REFERENCE_C_CODE */
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#ifdef CONFIG_DARWIN
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register const vector float vczero = (const vector float)(0.);
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#else
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register const vector float vczero = (const vector float){0.,0.,0.,0.};
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#endif
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int ln = s->nbits;
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int j, np, np2;
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int nblocks, nloops;
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register FFTComplex *p, *q;
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FFTComplex *cptr, *cptr1;
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int k;
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POWERPC_TBL_START_COUNT(altivec_fft_num, s->nbits >= 6);
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np = 1 << ln;
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{
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vector float *r, a, b, a1, c1, c2;
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r = (vector float *)&z[0];
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c1 = vcii(p,p,n,n);
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if (s->inverse)
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{
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c2 = vcii(p,p,n,p);
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}
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else
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{
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c2 = vcii(p,p,p,n);
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}
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j = (np >> 2);
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do {
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a = vec_ld(0, r);
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a1 = vec_ld(sizeof(vector float), r);
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b = vec_perm(a,a,vcprmle(1,0,3,2));
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a = vec_madd(a,c1,b);
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/* do the pass 0 butterfly */
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b = vec_perm(a1,a1,vcprmle(1,0,3,2));
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b = vec_madd(a1,c1,b);
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/* do the pass 0 butterfly */
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/* multiply third by -i */
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b = vec_perm(b,b,vcprmle(2,3,1,0));
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/* do the pass 1 butterfly */
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vec_st(vec_madd(b,c2,a), 0, r);
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vec_st(vec_nmsub(b,c2,a), sizeof(vector float), r);
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r += 2;
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} while (--j != 0);
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}
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/* pass 2 .. ln-1 */
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nblocks = np >> 3;
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nloops = 1 << 2;
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np2 = np >> 1;
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cptr1 = s->exptab1;
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do {
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p = z;
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q = z + nloops;
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j = nblocks;
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do {
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cptr = cptr1;
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k = nloops >> 1;
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do {
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vector float a,b,c,t1;
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a = vec_ld(0, (float*)p);
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b = vec_ld(0, (float*)q);
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/* complex mul */
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c = vec_ld(0, (float*)cptr);
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/* cre*re cim*re */
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t1 = vec_madd(c, vec_perm(b,b,vcprmle(2,2,0,0)),vczero);
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c = vec_ld(sizeof(vector float), (float*)cptr);
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/* -cim*im cre*im */
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b = vec_madd(c, vec_perm(b,b,vcprmle(3,3,1,1)),t1);
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/* butterfly */
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vec_st(vec_add(a,b), 0, (float*)p);
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vec_st(vec_sub(a,b), 0, (float*)q);
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p += 2;
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q += 2;
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cptr += 4;
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} while (--k);
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p += nloops;
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q += nloops;
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} while (--j);
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cptr1 += nloops * 2;
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nblocks = nblocks >> 1;
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nloops = nloops << 1;
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} while (nblocks != 0);
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POWERPC_TBL_STOP_COUNT(altivec_fft_num, s->nbits >= 6);
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#endif /* ALTIVEC_USE_REFERENCE_C_CODE */
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}
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