FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
fft_init.c
Go to the documentation of this file.
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"
27 #include "libavcodec/fft.h"
28 
29 /**
30  * Do a complex FFT with the parameters defined in ff_fft_init().
31  * The input data must be permuted before with s->revtab table.
32  * No 1.0 / sqrt(n) normalization is done.
33  * AltiVec-enabled:
34  * This code assumes that the 'z' pointer is 16 bytes-aligned.
35  * It also assumes all FFTComplex are 8 bytes-aligned pairs of floats.
36  */
37 
38 #if HAVE_VSX
39 #include "fft_vsx.h"
40 #else
43 #endif
44 
45 #if HAVE_GNU_AS && HAVE_ALTIVEC && (HAVE_BIGENDIAN || HAVE_VSX)
46 static void imdct_half_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
47 {
48  int j, k;
49  int n = 1 << s->mdct_bits;
50  int n4 = n >> 2;
51  int n8 = n >> 3;
52  int n32 = n >> 5;
53  const uint16_t *revtabj = s->revtab;
54  const uint16_t *revtabk = s->revtab+n4;
55  const vec_f *tcos = (const vec_f*)(s->tcos+n8);
56  const vec_f *tsin = (const vec_f*)(s->tsin+n8);
57  const vec_f *pin = (const vec_f*)(input+n4);
58  vec_f *pout = (vec_f*)(output+n4);
59 
60  /* pre rotation */
61  k = n32-1;
62  do {
63  vec_f cos,sin,cos0,sin0,cos1,sin1,re,im,r0,i0,r1,i1,a,b,c,d;
64 #define CMULA(p,o0,o1,o2,o3)\
65  a = pin[ k*2+p]; /* { z[k].re, z[k].im, z[k+1].re, z[k+1].im } */\
66  b = pin[-k*2-p-1]; /* { z[-k-2].re, z[-k-2].im, z[-k-1].re, z[-k-1].im } */\
67  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 } */\
68  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 } */\
69  cos = vec_perm(cos0, cos1, vcprm(o0,o1,s##o2,s##o3)); /* { cos[k], cos[k+1], cos[-k-2], cos[-k-1] } */\
70  sin = vec_perm(sin0, sin1, vcprm(o0,o1,s##o2,s##o3));\
71  r##p = im*cos - re*sin;\
72  i##p = re*cos + im*sin;
73 #define STORE2(v,dst)\
74  j = dst;\
75  vec_ste(v, 0, output+j*2);\
76  vec_ste(v, 4, output+j*2);
77 #define STORE8(p)\
78  a = vec_perm(r##p, i##p, vcprm(0,s0,0,s0));\
79  b = vec_perm(r##p, i##p, vcprm(1,s1,1,s1));\
80  c = vec_perm(r##p, i##p, vcprm(2,s2,2,s2));\
81  d = vec_perm(r##p, i##p, vcprm(3,s3,3,s3));\
82  STORE2(a, revtabk[ p*2-4]);\
83  STORE2(b, revtabk[ p*2-3]);\
84  STORE2(c, revtabj[-p*2+2]);\
85  STORE2(d, revtabj[-p*2+3]);
86 
87  cos0 = tcos[k];
88  sin0 = tsin[k];
89  cos1 = tcos[-k-1];
90  sin1 = tsin[-k-1];
91  CMULA(0, 0,1,2,3);
92  CMULA(1, 2,3,0,1);
93  STORE8(0);
94  STORE8(1);
95  revtabj += 4;
96  revtabk -= 4;
97  k--;
98  } while(k >= 0);
99 
100 #if HAVE_VSX
101  ff_fft_calc_vsx(s, (FFTComplex*)output);
102 #else
103  ff_fft_calc_altivec(s, (FFTComplex*)output);
104 #endif
105 
106  /* post rotation + reordering */
107  j = -n32;
108  k = n32-1;
109  do {
110  vec_f cos,sin,re,im,a,b,c,d;
111 #define CMULB(d0,d1,o)\
112  re = pout[o*2];\
113  im = pout[o*2+1];\
114  cos = tcos[o];\
115  sin = tsin[o];\
116  d0 = im*sin - re*cos;\
117  d1 = re*sin + im*cos;
118 
119  CMULB(a,b,j);
120  CMULB(c,d,k);
121  pout[2*j] = vec_perm(a, d, vcprm(0,s3,1,s2));
122  pout[2*j+1] = vec_perm(a, d, vcprm(2,s1,3,s0));
123  pout[2*k] = vec_perm(c, b, vcprm(0,s3,1,s2));
124  pout[2*k+1] = vec_perm(c, b, vcprm(2,s1,3,s0));
125  j++;
126  k--;
127  } while(k >= 0);
128 }
129 
130 static void imdct_calc_altivec(FFTContext *s, FFTSample *output, const FFTSample *input)
131 {
132  int k;
133  int n = 1 << s->mdct_bits;
134  int n4 = n >> 2;
135  int n16 = n >> 4;
136  vec_u32 sign = {1U<<31,1U<<31,1U<<31,1U<<31};
137  vec_u32 *p0 = (vec_u32*)(output+n4);
138  vec_u32 *p1 = (vec_u32*)(output+n4*3);
139 
140  imdct_half_altivec(s, output + n4, input);
141 
142  for (k = 0; k < n16; k++) {
143  vec_u32 a = p0[k] ^ sign;
144  vec_u32 b = p1[-k-1];
145  p0[-k-1] = vec_perm(a, a, vcprm(3,2,1,0));
146  p1[k] = vec_perm(b, b, vcprm(3,2,1,0));
147  }
148 }
149 #endif /* HAVE_GNU_AS && HAVE_ALTIVEC && (HAVE_BIGENDIAN || HAVE_VSX) */
150 
152 {
153 #if HAVE_GNU_AS && HAVE_ALTIVEC && (HAVE_BIGENDIAN || HAVE_VSX)
155  return;
156 
157 #if HAVE_VSX
158  s->fft_calc = ff_fft_calc_interleave_vsx;
159 #else
161 #endif
162  if (s->mdct_bits >= 5) {
163  s->imdct_calc = imdct_calc_altivec;
164  s->imdct_half = imdct_half_altivec;
165  }
166 #endif /* HAVE_GNU_AS && HAVE_ALTIVEC && HAVE_BIGENDIAN */
167 }
#define vec_f
Definition: util_altivec.h:40
const char * s
Definition: avisynth_c.h:768
float re
Definition: fft.c:82
const char * b
Definition: vf_curves.c:113
av_cold void ff_fft_init_ppc(FFTContext *s)
Definition: fft_init.c:151
#define av_cold
Definition: attributes.h:82
#define U(x)
Definition: vp56_arith.h:37
#define s2
Definition: regdef.h:39
#define PPC_ALTIVEC(flags)
Definition: cpu.h:26
#define s0
Definition: regdef.h:37
float FFTSample
Definition: avfft.h:35
void(* imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input)
Definition: fft.h:107
void ff_fft_calc_interleave_altivec(FFTContext *s, FFTComplex *z)
Definition: fft.h:88
FFTSample * tsin
Definition: fft.h:97
int n
Definition: avisynth_c.h:684
#define s3
Definition: regdef.h:40
void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in ff_fft_init().
#define vec_u32
Definition: util_altivec.h:38
void(* imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input)
Definition: fft.h:108
int mdct_bits
Definition: fft.h:94
float im
Definition: fft.c:82
#define s1
Definition: regdef.h:38
int av_get_cpu_flags(void)
Return the flags which specify extensions supported by the CPU.
Definition: cpu.c:92
Contains misc utility macros and inline functions.
static double c[64]
FFTSample * tcos
Definition: fft.h:96
void(* fft_calc)(struct FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in ff_fft_init().
Definition: fft.h:106
uint16_t * revtab
Definition: fft.h:91