1/*
2 * FFT/IFFT transforms
3 * AltiVec-enabled
4 * Copyright (c) 2009 Loren Merritt
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include "config.h"
24#include "libavutil/cpu.h"
25#include "libavutil/ppc/cpu.h"
26#include "libavutil/ppc/types_altivec.h"
27#include "libavutil/ppc/util_altivec.h"
28#include "libavcodec/fft.h"
29
30/**
31 * Do a complex FFT with the parameters defined in ff_fft_init().
32 * The input data must be permuted before with s->revtab table.
33 * No 1.0 / sqrt(n) normalization is done.
34 * AltiVec-enabled:
35 * This code assumes that the 'z' pointer is 16 bytes-aligned.
36 * It also assumes all FFTComplex are 8 bytes-aligned pairs of floats.
37 */
38
39#if HAVE_VSX
40#include "fft_vsx.h"
41#else
42void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z);
43void ff_fft_calc_interleave_altivec(FFTContext *s, FFTComplex *z);
44#endif
45
46#if HAVE_GNU_AS && HAVE_ALTIVEC
47static void imdct_half_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
48{
49    int j, k;
50    int n = 1 << s->mdct_bits;
51    int n4 = n >> 2;
52    int n8 = n >> 3;
53    int n32 = n >> 5;
54    const uint16_t *revtabj = s->revtab;
55    const uint16_t *revtabk = s->revtab+n4;
56    const vec_f *tcos = (const vec_f*)(s->tcos+n8);
57    const vec_f *tsin = (const vec_f*)(s->tsin+n8);
58    const vec_f *pin = (const vec_f*)(input+n4);
59    vec_f *pout = (vec_f*)(output+n4);
60
61    /* pre rotation */
62    k = n32-1;
63    do {
64        vec_f cos,sin,cos0,sin0,cos1,sin1,re,im,r0,i0,r1,i1,a,b,c,d;
65#define CMULA(p,o0,o1,o2,o3)\
66        a = pin[ k*2+p];                       /* { z[k].re,    z[k].im,    z[k+1].re,  z[k+1].im  } */\
67        b = pin[-k*2-p-1];                     /* { z[-k-2].re, z[-k-2].im, z[-k-1].re, z[-k-1].im } */\
68        re = vec_perm(a, b, vcprm(0,2,s0,s2)); /* { z[k].re,    z[k+1].re,  z[-k-2].re, z[-k-1].re } */\
69        im = vec_perm(a, b, vcprm(s3,s1,3,1)); /* { z[-k-1].im, z[-k-2].im, z[k+1].im,  z[k].im    } */\
70        cos = vec_perm(cos0, cos1, vcprm(o0,o1,s##o2,s##o3)); /* { cos[k], cos[k+1], cos[-k-2], cos[-k-1] } */\
71        sin = vec_perm(sin0, sin1, vcprm(o0,o1,s##o2,s##o3));\
72        r##p = im*cos - re*sin;\
73        i##p = re*cos + im*sin;
74#define STORE2(v,dst)\
75        j = dst;\
76        vec_ste(v, 0, output+j*2);\
77        vec_ste(v, 4, output+j*2);
78#define STORE8(p)\
79        a = vec_perm(r##p, i##p, vcprm(0,s0,0,s0));\
80        b = vec_perm(r##p, i##p, vcprm(1,s1,1,s1));\
81        c = vec_perm(r##p, i##p, vcprm(2,s2,2,s2));\
82        d = vec_perm(r##p, i##p, vcprm(3,s3,3,s3));\
83        STORE2(a, revtabk[ p*2-4]);\
84        STORE2(b, revtabk[ p*2-3]);\
85        STORE2(c, revtabj[-p*2+2]);\
86        STORE2(d, revtabj[-p*2+3]);
87
88        cos0 = tcos[k];
89        sin0 = tsin[k];
90        cos1 = tcos[-k-1];
91        sin1 = tsin[-k-1];
92        CMULA(0, 0,1,2,3);
93        CMULA(1, 2,3,0,1);
94        STORE8(0);
95        STORE8(1);
96        revtabj += 4;
97        revtabk -= 4;
98        k--;
99    } while(k >= 0);
100
101#if HAVE_VSX
102    ff_fft_calc_vsx(s, (FFTComplex*)output);
103#else
104    ff_fft_calc_altivec(s, (FFTComplex*)output);
105#endif
106
107    /* post rotation + reordering */
108    j = -n32;
109    k = n32-1;
110    do {
111        vec_f cos,sin,re,im,a,b,c,d;
112#define CMULB(d0,d1,o)\
113        re = pout[o*2];\
114        im = pout[o*2+1];\
115        cos = tcos[o];\
116        sin = tsin[o];\
117        d0 = im*sin - re*cos;\
118        d1 = re*sin + im*cos;
119
120        CMULB(a,b,j);
121        CMULB(c,d,k);
122        pout[2*j]   = vec_perm(a, d, vcprm(0,s3,1,s2));
123        pout[2*j+1] = vec_perm(a, d, vcprm(2,s1,3,s0));
124        pout[2*k]   = vec_perm(c, b, vcprm(0,s3,1,s2));
125        pout[2*k+1] = vec_perm(c, b, vcprm(2,s1,3,s0));
126        j++;
127        k--;
128    } while(k >= 0);
129}
130
131static void imdct_calc_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
132{
133    int k;
134    int n = 1 << s->mdct_bits;
135    int n4 = n >> 2;
136    int n16 = n >> 4;
137    vec_u32 sign = {1U<<31,1U<<31,1U<<31,1U<<31};
138    vec_u32 *p0 = (vec_u32*)(output+n4);
139    vec_u32 *p1 = (vec_u32*)(output+n4*3);
140
141    imdct_half_altivec(s, output + n4, input);
142
143    for (k = 0; k < n16; k++) {
144        vec_u32 a = p0[k] ^ sign;
145        vec_u32 b = p1[-k-1];
146        p0[-k-1] = vec_perm(a, a, vcprm(3,2,1,0));
147        p1[k]    = vec_perm(b, b, vcprm(3,2,1,0));
148    }
149}
150#endif /* HAVE_GNU_AS && HAVE_ALTIVEC */
151
152av_cold void ff_fft_init_ppc(FFTContext *s)
153{
154#if HAVE_GNU_AS && HAVE_ALTIVEC
155    if (!PPC_ALTIVEC(av_get_cpu_flags()))
156        return;
157
158#if HAVE_VSX
159    s->fft_calc = ff_fft_calc_interleave_vsx;
160#else
161    s->fft_calc   = ff_fft_calc_interleave_altivec;
162#endif
163    if (s->mdct_bits >= 5) {
164        s->imdct_calc = imdct_calc_altivec;
165        s->imdct_half = imdct_half_altivec;
166    }
167#endif /* HAVE_GNU_AS && HAVE_ALTIVEC */
168}
169