Libav
fft_init.c
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1 /*
2  * FFT/IFFT transforms
3  * AltiVec-enabled
4  * Copyright (c) 2009 Loren Merritt
5  *
6  * This file is part of Libav.
7  *
8  * Libav 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  * Libav 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 Libav; 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"
28 #include "libavcodec/fft.h"
29 
41 
42 #if HAVE_GNU_AS && HAVE_ALTIVEC
43 static void imdct_half_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
44 {
45  int j, k;
46  int n = 1 << s->mdct_bits;
47  int n4 = n >> 2;
48  int n8 = n >> 3;
49  int n32 = n >> 5;
50  const uint16_t *revtabj = s->revtab;
51  const uint16_t *revtabk = s->revtab+n4;
52  const vec_f *tcos = (const vec_f*)(s->tcos+n8);
53  const vec_f *tsin = (const vec_f*)(s->tsin+n8);
54  const vec_f *pin = (const vec_f*)(input+n4);
55  vec_f *pout = (vec_f*)(output+n4);
56 
57  /* pre rotation */
58  k = n32-1;
59  do {
60  vec_f cos,sin,cos0,sin0,cos1,sin1,re,im,r0,i0,r1,i1,a,b,c,d;
61 #define CMULA(p,o0,o1,o2,o3)\
62  a = pin[ k*2+p]; /* { z[k].re, z[k].im, z[k+1].re, z[k+1].im } */\
63  b = pin[-k*2-p-1]; /* { z[-k-2].re, z[-k-2].im, z[-k-1].re, z[-k-1].im } */\
64  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 } */\
65  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 } */\
66  cos = vec_perm(cos0, cos1, vcprm(o0,o1,s##o2,s##o3)); /* { cos[k], cos[k+1], cos[-k-2], cos[-k-1] } */\
67  sin = vec_perm(sin0, sin1, vcprm(o0,o1,s##o2,s##o3));\
68  r##p = im*cos - re*sin;\
69  i##p = re*cos + im*sin;
70 #define STORE2(v,dst)\
71  j = dst;\
72  vec_ste(v, 0, output+j*2);\
73  vec_ste(v, 4, output+j*2);
74 #define STORE8(p)\
75  a = vec_perm(r##p, i##p, vcprm(0,s0,0,s0));\
76  b = vec_perm(r##p, i##p, vcprm(1,s1,1,s1));\
77  c = vec_perm(r##p, i##p, vcprm(2,s2,2,s2));\
78  d = vec_perm(r##p, i##p, vcprm(3,s3,3,s3));\
79  STORE2(a, revtabk[ p*2-4]);\
80  STORE2(b, revtabk[ p*2-3]);\
81  STORE2(c, revtabj[-p*2+2]);\
82  STORE2(d, revtabj[-p*2+3]);
83 
84  cos0 = tcos[k];
85  sin0 = tsin[k];
86  cos1 = tcos[-k-1];
87  sin1 = tsin[-k-1];
88  CMULA(0, 0,1,2,3);
89  CMULA(1, 2,3,0,1);
90  STORE8(0);
91  STORE8(1);
92  revtabj += 4;
93  revtabk -= 4;
94  k--;
95  } while(k >= 0);
96 
97  ff_fft_calc_altivec(s, (FFTComplex*)output);
98 
99  /* post rotation + reordering */
100  j = -n32;
101  k = n32-1;
102  do {
103  vec_f cos,sin,re,im,a,b,c,d;
104 #define CMULB(d0,d1,o)\
105  re = pout[o*2];\
106  im = pout[o*2+1];\
107  cos = tcos[o];\
108  sin = tsin[o];\
109  d0 = im*sin - re*cos;\
110  d1 = re*sin + im*cos;
111 
112  CMULB(a,b,j);
113  CMULB(c,d,k);
114  pout[2*j] = vec_perm(a, d, vcprm(0,s3,1,s2));
115  pout[2*j+1] = vec_perm(a, d, vcprm(2,s1,3,s0));
116  pout[2*k] = vec_perm(c, b, vcprm(0,s3,1,s2));
117  pout[2*k+1] = vec_perm(c, b, vcprm(2,s1,3,s0));
118  j++;
119  k--;
120  } while(k >= 0);
121 }
122 
123 static void imdct_calc_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
124 {
125  int k;
126  int n = 1 << s->mdct_bits;
127  int n4 = n >> 2;
128  int n16 = n >> 4;
129  vec_u32 sign = {1U<<31,1U<<31,1U<<31,1U<<31};
130  vec_u32 *p0 = (vec_u32*)(output+n4);
131  vec_u32 *p1 = (vec_u32*)(output+n4*3);
132 
133  imdct_half_altivec(s, output + n4, input);
134 
135  for (k = 0; k < n16; k++) {
136  vec_u32 a = p0[k] ^ sign;
137  vec_u32 b = p1[-k-1];
138  p0[-k-1] = vec_perm(a, a, vcprm(3,2,1,0));
139  p1[k] = vec_perm(b, b, vcprm(3,2,1,0));
140  }
141 }
142 #endif /* HAVE_GNU_AS && HAVE_ALTIVEC */
143 
145 {
146 #if HAVE_GNU_AS && HAVE_ALTIVEC
148  return;
149 
151  if (s->mdct_bits >= 5) {
152  s->imdct_calc = imdct_calc_altivec;
153  s->imdct_half = imdct_half_altivec;
154  }
155 #endif /* HAVE_GNU_AS && HAVE_ALTIVEC */
156 }
av_cold void ff_fft_init_ppc(FFTContext *s)
Definition: fft_init.c:144
#define av_cold
Definition: attributes.h:66
#define b
Definition: input.c:52
#define PPC_ALTIVEC(flags)
Definition: cpu.h:26
void(* imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input)
Definition: fft.h:92
float FFTSample
Definition: avfft.h:35
void ff_fft_calc_interleave_altivec(FFTContext *s, FFTComplex *z)
Definition: fft.h:73
FFTSample * tsin
Definition: fft.h:82
#define vec_u32
Definition: types_altivec.h:31
void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in ff_fft_init().
float im
Definition: fft-test.c:69
int mdct_bits
Definition: fft.h:79
int av_get_cpu_flags(void)
Return the flags which specify extensions supported by the CPU.
Definition: cpu.c:47
void(* imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input)
Definition: fft.h:93
Contains misc utility macros and inline functions.
void(* fft_calc)(struct FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in ff_fft_init().
Definition: fft.h:91
FFTSample * tcos
Definition: fft.h:81
float re
Definition: fft-test.c:69
uint16_t * revtab
Definition: fft.h:76
#define vec_f
Definition: types_altivec.h:33
Definition: vf_drawbox.c:37