4 * Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>
5 * Based on code Copyright (c) 2002 Fabrice Bellard.
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include "../dsputil.h"
23 #include "dsputil_altivec.h"
26 those three macros are from libavcodec/fft.c
27 and are required for the reference C code
30 #define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
32 FFTSample ax, ay, bx, by;\
42 #define MUL16(a,b) ((a) * (b))
43 #define CMUL(pre, pim, are, aim, bre, bim) \
45 pre = (MUL16(are, bre) - MUL16(aim, bim));\
46 pim = (MUL16(are, bim) + MUL16(bre, aim));\
51 * Do a complex FFT with the parameters defined in fft_init(). The
52 * input data must be permuted before with s->revtab table. No
53 * 1.0/sqrt(n) normalization is done.
55 * This code assumes that the 'z' pointer is 16 bytes-aligned
56 * It also assumes all FFTComplex are 8 bytes-aligned pair of float
57 * The code is exactly the same as the SSE version, except
58 * that successive MUL + ADD/SUB have been merged into
59 * fused multiply-add ('vec_madd' in altivec)
61 void fft_calc_altivec(FFTContext *s, FFTComplex *z)
63 POWERPC_TBL_DECLARE(altivec_fft_num, s->nbits >= 6);
64 #ifdef ALTIVEC_USE_REFERENCE_C_CODE
68 register FFTComplex *p, *q;
69 FFTComplex *exptab = s->exptab;
71 FFTSample tmp_re, tmp_im;
73 POWERPC_TBL_START_COUNT(altivec_fft_num, s->nbits >= 6);
82 BF(p[0].re, p[0].im, p[1].re, p[1].im,
83 p[0].re, p[0].im, p[1].re, p[1].im);
94 BF(p[0].re, p[0].im, p[2].re, p[2].im,
95 p[0].re, p[0].im, p[2].re, p[2].im);
96 BF(p[1].re, p[1].im, p[3].re, p[3].im,
97 p[1].re, p[1].im, -p[3].im, p[3].re);
102 BF(p[0].re, p[0].im, p[2].re, p[2].im,
103 p[0].re, p[0].im, p[2].re, p[2].im);
104 BF(p[1].re, p[1].im, p[3].re, p[3].im,
105 p[1].re, p[1].im, p[3].im, -p[3].re);
117 for (j = 0; j < nblocks; ++j) {
118 BF(p->re, p->im, q->re, q->im,
119 p->re, p->im, q->re, q->im);
123 for(l = nblocks; l < np2; l += nblocks) {
124 CMUL(tmp_re, tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
125 BF(p->re, p->im, q->re, q->im,
126 p->re, p->im, tmp_re, tmp_im);
134 nblocks = nblocks >> 1;
135 nloops = nloops << 1;
136 } while (nblocks != 0);
138 POWERPC_TBL_STOP_COUNT(altivec_fft_num, s->nbits >= 6);
140 #else /* ALTIVEC_USE_REFERENCE_C_CODE */
141 register const vector float vczero = (const vector float)(0.);
146 register FFTComplex *p, *q;
147 FFTComplex *cptr, *cptr1;
150 POWERPC_TBL_START_COUNT(altivec_fft_num, s->nbits >= 6);
155 vector float *r, a, b, a1, c1, c2;
157 r = (vector float *)&z[0];
173 a1 = vec_ld(sizeof(vector float), r);
175 b = vec_perm(a,a,vcprmle(1,0,3,2));
176 a = vec_madd(a,c1,b);
177 /* do the pass 0 butterfly */
179 b = vec_perm(a1,a1,vcprmle(1,0,3,2));
180 b = vec_madd(a1,c1,b);
181 /* do the pass 0 butterfly */
183 /* multiply third by -i */
184 b = vec_perm(b,b,vcprmle(2,3,1,0));
186 /* do the pass 1 butterfly */
187 vec_st(vec_madd(b,c2,a), 0, r);
188 vec_st(vec_nmsub(b,c2,a), sizeof(vector float), r);
208 vector float a,b,c,t1;
210 a = vec_ld(0, (float*)p);
211 b = vec_ld(0, (float*)q);
214 c = vec_ld(0, (float*)cptr);
216 t1 = vec_madd(c, vec_perm(b,b,vcprmle(2,2,0,0)),vczero);
217 c = vec_ld(sizeof(vector float), (float*)cptr);
219 b = vec_madd(c, vec_perm(b,b,vcprmle(3,3,1,1)),t1);
222 vec_st(vec_add(a,b), 0, (float*)p);
223 vec_st(vec_sub(a,b), 0, (float*)q);
234 nblocks = nblocks >> 1;
235 nloops = nloops << 1;
236 } while (nblocks != 0);
238 POWERPC_TBL_STOP_COUNT(altivec_fft_num, s->nbits >= 6);
240 #endif /* ALTIVEC_USE_REFERENCE_C_CODE */