Commit 5d0ddd1a authored by Loren Merritt's avatar Loren Merritt
Browse files

split-radix FFT

c is 1.9x faster than previous c (on various x86 cpus), sse is 1.6x faster than previous sse.

Originally committed as revision 14698 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent bafad220
......@@ -388,6 +388,8 @@ OBJS += i386/fdct_mmx.o \
i386/simple_idct_mmx.o \
i386/idct_mmx_xvid.o \
i386/idct_sse2_xvid.o \
OBJS-$(HAVE_YASM) += i386/fft_mmx.o \
i386/fft_sse.o \
i386/fft_3dn.o \
i386/fft_3dn2.o \
......
......@@ -639,6 +639,8 @@ typedef struct FFTContext {
uint16_t *revtab;
FFTComplex *exptab;
FFTComplex *exptab1; /* only used by SSE code */
FFTComplex *tmp_buf;
void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
void (*imdct_calc)(struct MDCTContext *s, FFTSample *output,
const FFTSample *input, FFTSample *tmp);
......@@ -647,13 +649,18 @@ typedef struct FFTContext {
} FFTContext;
int ff_fft_init(FFTContext *s, int nbits, int inverse);
void ff_fft_permute(FFTContext *s, FFTComplex *z);
void ff_fft_permute_c(FFTContext *s, FFTComplex *z);
void ff_fft_permute_sse(FFTContext *s, FFTComplex *z);
void ff_fft_calc_c(FFTContext *s, FFTComplex *z);
void ff_fft_calc_sse(FFTContext *s, FFTComplex *z);
void ff_fft_calc_3dn(FFTContext *s, FFTComplex *z);
void ff_fft_calc_3dn2(FFTContext *s, FFTComplex *z);
void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z);
static inline void ff_fft_permute(FFTContext *s, FFTComplex *z)
{
s->fft_permute(s, z);
}
static inline void ff_fft_calc(FFTContext *s, FFTComplex *z)
{
s->fft_calc(s, z);
......
/*
* FFT/IFFT transforms
* Copyright (c) 2008 Loren Merritt
* Copyright (c) 2002 Fabrice Bellard.
* Partly based on libdjbfft by D. J. Bernstein
*
* This file is part of FFmpeg.
*
......@@ -26,6 +28,36 @@
#include "dsputil.h"
/* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
DECLARE_ALIGNED_16(FFTSample, ff_cos_16[8]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_32[16]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_64[32]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_128[64]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_256[128]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_512[256]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_1024[512]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_2048[1024]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_4096[2048]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_8192[4096]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_16384[8192]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_32768[16384]);
DECLARE_ALIGNED_16(FFTSample, ff_cos_65536[32768]);
static FFTSample *ff_cos_tabs[] = {
ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256, ff_cos_512, ff_cos_1024,
ff_cos_2048, ff_cos_4096, ff_cos_8192, ff_cos_16384, ff_cos_32768, ff_cos_65536,
};
static int split_radix_permutation(int i, int n, int inverse)
{
int m;
if(n <= 2) return i&1;
m = n >> 1;
if(!(i&m)) return split_radix_permutation(i, m, inverse)*2;
m >>= 1;
if(inverse == !(i&m)) return split_radix_permutation(i, m, inverse)*4 + 1;
else return split_radix_permutation(i, m, inverse)*4 - 1;
}
/**
* The size of the FFT is 2^nbits. If inverse is TRUE, inverse FFT is
* done
......@@ -34,12 +66,15 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
{
int i, j, m, n;
float alpha, c1, s1, s2;
int shuffle = 0;
int split_radix = 1;
int av_unused has_vectors;
if (nbits < 2 || nbits > 16)
goto fail;
s->nbits = nbits;
n = 1 << nbits;
s->tmp_buf = NULL;
s->exptab = av_malloc((n / 2) * sizeof(FFTComplex));
if (!s->exptab)
goto fail;
......@@ -50,50 +85,62 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
s2 = inverse ? 1.0 : -1.0;
for(i=0;i<(n/2);i++) {
alpha = 2 * M_PI * (float)i / (float)n;
c1 = cos(alpha);
s1 = sin(alpha) * s2;
s->exptab[i].re = c1;
s->exptab[i].im = s1;
}
s->fft_permute = ff_fft_permute_c;
s->fft_calc = ff_fft_calc_c;
s->imdct_calc = ff_imdct_calc;
s->imdct_half = ff_imdct_half;
s->exptab1 = NULL;
#ifdef HAVE_MMX
#if defined HAVE_MMX && defined HAVE_YASM
has_vectors = mm_support();
shuffle = 1;
if (has_vectors & MM_3DNOWEXT) {
/* 3DNowEx for K7/K8 */
if (has_vectors & MM_SSE) {
/* SSE for P3/P4/K8 */
s->imdct_calc = ff_imdct_calc_sse;
s->imdct_half = ff_imdct_half_sse;
s->fft_permute = ff_fft_permute_sse;
s->fft_calc = ff_fft_calc_sse;
} else if (has_vectors & MM_3DNOWEXT) {
/* 3DNowEx for K7 */
s->imdct_calc = ff_imdct_calc_3dn2;
s->imdct_half = ff_imdct_half_3dn2;
s->fft_calc = ff_fft_calc_3dn2;
} else if (has_vectors & MM_3DNOW) {
/* 3DNow! for K6-2/3 */
s->fft_calc = ff_fft_calc_3dn;
} else if (has_vectors & MM_SSE) {
/* SSE for P3/P4 */
s->imdct_calc = ff_imdct_calc_sse;
s->imdct_half = ff_imdct_half_sse;
s->fft_calc = ff_fft_calc_sse;
} else {
shuffle = 0;
}
#elif defined HAVE_ALTIVEC && !defined ALTIVEC_USE_REFERENCE_C_CODE
has_vectors = mm_support();
if (has_vectors & MM_ALTIVEC) {
s->fft_calc = ff_fft_calc_altivec;
shuffle = 1;
split_radix = 0;
}
#endif
/* compute constant table for HAVE_SSE version */
if (shuffle) {
if (split_radix) {
for(j=4; j<=nbits; j++) {
int m = 1<<j;
double freq = 2*M_PI/m;
FFTSample *tab = ff_cos_tabs[j-4];
for(i=0; i<=m/4; i++)
tab[i] = cos(i*freq);
for(i=1; i<m/4; i++)
tab[m/2-i] = tab[i];
}
for(i=0; i<n; i++)
s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = i;
s->tmp_buf = av_malloc(n * sizeof(FFTComplex));
} else {
int np, nblocks, np2, l;
FFTComplex *q;
for(i=0; i<(n/2); i++) {
alpha = 2 * M_PI * (float)i / (float)n;
c1 = cos(alpha);
s1 = sin(alpha) * s2;
s->exptab[i].re = c1;
s->exptab[i].im = s1;
}
np = 1 << nbits;
nblocks = np >> 3;
np2 = np >> 1;
......@@ -116,7 +163,6 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
nblocks = nblocks >> 1;
} while (nblocks != 0);
av_freep(&s->exptab);
}
/* compute bit reverse table */
......@@ -127,126 +173,35 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
}
s->revtab[i]=m;
}
}
return 0;
fail:
av_freep(&s->revtab);
av_freep(&s->exptab);
av_freep(&s->exptab1);
av_freep(&s->tmp_buf);
return -1;
}
/* butter fly op */
#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
{\
FFTSample ax, ay, bx, by;\
bx=pre1;\
by=pim1;\
ax=qre1;\
ay=qim1;\
pre = (bx + ax);\
pim = (by + ay);\
qre = (bx - ax);\
qim = (by - ay);\
}
#define MUL16(a,b) ((a) * (b))
#define CMUL(pre, pim, are, aim, bre, bim) \
{\
pre = (MUL16(are, bre) - MUL16(aim, bim));\
pim = (MUL16(are, bim) + MUL16(bre, aim));\
}
/**
* Do a complex FFT with the parameters defined in ff_fft_init(). The
* input data must be permuted before with s->revtab table. No
* 1.0/sqrt(n) normalization is done.
*/
void ff_fft_calc_c(FFTContext *s, FFTComplex *z)
{
int ln = s->nbits;
int j, np, np2;
int nblocks, nloops;
register FFTComplex *p, *q;
FFTComplex *exptab = s->exptab;
int l;
FFTSample tmp_re, tmp_im;
np = 1 << ln;
/* pass 0 */
p=&z[0];
j=(np >> 1);
do {
BF(p[0].re, p[0].im, p[1].re, p[1].im,
p[0].re, p[0].im, p[1].re, p[1].im);
p+=2;
} while (--j != 0);
/* pass 1 */
p=&z[0];
j=np >> 2;
if (s->inverse) {
do {
BF(p[0].re, p[0].im, p[2].re, p[2].im,
p[0].re, p[0].im, p[2].re, p[2].im);
BF(p[1].re, p[1].im, p[3].re, p[3].im,
p[1].re, p[1].im, -p[3].im, p[3].re);
p+=4;
} while (--j != 0);
} else {
do {
BF(p[0].re, p[0].im, p[2].re, p[2].im,
p[0].re, p[0].im, p[2].re, p[2].im);
BF(p[1].re, p[1].im, p[3].re, p[3].im,
p[1].re, p[1].im, p[3].im, -p[3].re);
p+=4;
} while (--j != 0);
}
/* pass 2 .. ln-1 */
nblocks = np >> 3;
nloops = 1 << 2;
np2 = np >> 1;
do {
p = z;
q = z + nloops;
for (j = 0; j < nblocks; ++j) {
BF(p->re, p->im, q->re, q->im,
p->re, p->im, q->re, q->im);
p++;
q++;
for(l = nblocks; l < np2; l += nblocks) {
CMUL(tmp_re, tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
BF(p->re, p->im, q->re, q->im,
p->re, p->im, tmp_re, tmp_im);
p++;
q++;
}
p += nloops;
q += nloops;
}
nblocks = nblocks >> 1;
nloops = nloops << 1;
} while (nblocks != 0);
}
/**
* Do the permutation needed BEFORE calling ff_fft_calc()
*/
void ff_fft_permute(FFTContext *s, FFTComplex *z)
void ff_fft_permute_c(FFTContext *s, FFTComplex *z)
{
int j, k, np;
FFTComplex tmp;
const uint16_t *revtab = s->revtab;
np = 1 << s->nbits;
if (s->tmp_buf) {
/* TODO: handle split-radix permute in a more optimal way, probably in-place */
for(j=0;j<np;j++) s->tmp_buf[revtab[j]] = z[j];
memcpy(z, s->tmp_buf, np * sizeof(FFTComplex));
return;
}
/* reverse */
np = 1 << s->nbits;
for(j=0;j<np;j++) {
k = revtab[j];
if (k < j) {
......@@ -262,5 +217,169 @@ void ff_fft_end(FFTContext *s)
av_freep(&s->revtab);
av_freep(&s->exptab);
av_freep(&s->exptab1);
av_freep(&s->tmp_buf);
}
#define sqrthalf (float)M_SQRT1_2
#define BF(x,y,a,b) {\
x = a - b;\
y = a + b;\
}
#define BUTTERFLIES(a0,a1,a2,a3) {\
BF(t3, t5, t5, t1);\
BF(a2.re, a0.re, a0.re, t5);\
BF(a3.im, a1.im, a1.im, t3);\
BF(t4, t6, t2, t6);\
BF(a3.re, a1.re, a1.re, t4);\
BF(a2.im, a0.im, a0.im, t6);\
}
// force loading all the inputs before storing any.
// this is slightly slower for small data, but avoids store->load aliasing
// for addresses separated by large powers of 2.
#define BUTTERFLIES_BIG(a0,a1,a2,a3) {\
FFTSample r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\
BF(t3, t5, t5, t1);\
BF(a2.re, a0.re, r0, t5);\
BF(a3.im, a1.im, i1, t3);\
BF(t4, t6, t2, t6);\
BF(a3.re, a1.re, r1, t4);\
BF(a2.im, a0.im, i0, t6);\
}
#define TRANSFORM(a0,a1,a2,a3,wre,wim) {\
t1 = a2.re * wre + a2.im * wim;\
t2 = a2.im * wre - a2.re * wim;\
t5 = a3.re * wre - a3.im * wim;\
t6 = a3.im * wre + a3.re * wim;\
BUTTERFLIES(a0,a1,a2,a3)\
}
#define TRANSFORM_ZERO(a0,a1,a2,a3) {\
t1 = a2.re;\
t2 = a2.im;\
t5 = a3.re;\
t6 = a3.im;\
BUTTERFLIES(a0,a1,a2,a3)\
}
/* z[0...8n-1], w[1...2n-1] */
#define PASS(name)\
static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\
{\
FFTSample t1, t2, t3, t4, t5, t6;\
int o1 = 2*n;\
int o2 = 4*n;\
int o3 = 6*n;\
const FFTSample *wim = wre+o1;\
n--;\
\
TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\
TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
do {\
z += 2;\
wre += 2;\
wim -= 2;\
TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\
TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\
} while(--n);\
}
PASS(pass)
#undef BUTTERFLIES
#define BUTTERFLIES BUTTERFLIES_BIG
PASS(pass_big)
#define DECL_FFT(n,n2,n4)\
static void fft##n(FFTComplex *z)\
{\
fft##n2(z);\
fft##n4(z+n4*2);\
fft##n4(z+n4*3);\
pass(z,ff_cos_##n,n4/2);\
}
static void fft4(FFTComplex *z)
{
FFTSample t1, t2, t3, t4, t5, t6, t7, t8;
BF(t3, t1, z[0].re, z[1].re);
BF(t8, t6, z[3].re, z[2].re);
BF(z[2].re, z[0].re, t1, t6);
BF(t4, t2, z[0].im, z[1].im);
BF(t7, t5, z[2].im, z[3].im);
BF(z[3].im, z[1].im, t4, t8);
BF(z[3].re, z[1].re, t3, t7);
BF(z[2].im, z[0].im, t2, t5);
}
static void fft8(FFTComplex *z)
{
FFTSample t1, t2, t3, t4, t5, t6, t7, t8;
fft4(z);
BF(t1, z[5].re, z[4].re, -z[5].re);
BF(t2, z[5].im, z[4].im, -z[5].im);
BF(t3, z[7].re, z[6].re, -z[7].re);
BF(t4, z[7].im, z[6].im, -z[7].im);
BF(t8, t1, t3, t1);
BF(t7, t2, t2, t4);
BF(z[4].re, z[0].re, z[0].re, t1);
BF(z[4].im, z[0].im, z[0].im, t2);
BF(z[6].re, z[2].re, z[2].re, t7);
BF(z[6].im, z[2].im, z[2].im, t8);
TRANSFORM(z[1],z[3],z[5],z[7],sqrthalf,sqrthalf);
}
#ifndef CONFIG_SMALL
static void fft16(FFTComplex *z)
{
FFTSample t1, t2, t3, t4, t5, t6;
fft8(z);
fft4(z+8);
fft4(z+12);
TRANSFORM_ZERO(z[0],z[4],z[8],z[12]);
TRANSFORM(z[2],z[6],z[10],z[14],sqrthalf,sqrthalf);
TRANSFORM(z[1],z[5],z[9],z[13],ff_cos_16[1],ff_cos_16[3]);
TRANSFORM(z[3],z[7],z[11],z[15],ff_cos_16[3],ff_cos_16[1]);
}
#else
DECL_FFT(16,8,4)
#endif
DECL_FFT(32,16,8)
DECL_FFT(64,32,16)
DECL_FFT(128,64,32)
DECL_FFT(256,128,64)
DECL_FFT(512,256,128)
#ifndef CONFIG_SMALL
#define pass pass_big
#endif
DECL_FFT(1024,512,256)
DECL_FFT(2048,1024,512)
DECL_FFT(4096,2048,1024)
DECL_FFT(8192,4096,2048)
DECL_FFT(16384,8192,4096)
DECL_FFT(32768,16384,8192)
DECL_FFT(65536,32768,16384)
static void (*fft_dispatch[])(FFTComplex*) = {
fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024,
fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
};
/**
* Do a complex FFT with the parameters defined in ff_fft_init(). The
* input data must be permuted before with s->revtab table. No
* 1.0/sqrt(n) normalization is done.
*/
void ff_fft_calc_c(FFTContext *s, FFTComplex *z)
{
fft_dispatch[s->nbits-2](z);
}
/*
* FFT/MDCT transform with 3DNow! optimizations
* Copyright (c) 2006 Zuxy MENG Jie, Loren Merritt
* Based on fft_sse.c copyright (c) 2002 Fabrice Bellard.
* Copyright (c) 2008 Loren Merritt
*
* This file is part of FFmpeg.
*
......@@ -20,109 +19,5 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/x86_cpu.h"
#include "libavcodec/dsputil.h"
static const int p1m1[2] __attribute__((aligned(8))) =
{ 0, 1 << 31 };
static const int m1p1[2] __attribute__((aligned(8))) =
{ 1 << 31, 0 };
void ff_fft_calc_3dn(FFTContext *s, FFTComplex *z)
{
int ln = s->nbits;
long j;
x86_reg i;
long nblocks, nloops;
FFTComplex *p, *cptr;
asm volatile(
/* FEMMS is not a must here but recommended by AMD */
"femms \n\t"
"movq %0, %%mm7 \n\t"
::"m"(*(s->inverse ? m1p1 : p1m1))
);
i = 8 << ln;
asm volatile(
"1: \n\t"
"sub $32, %0 \n\t"
"movq (%0,%1), %%mm0 \n\t"
"movq 16(%0,%1), %%mm1 \n\t"
"movq 8(%0,%1), %%mm2 \n\t"
"movq 24(%0,%1), %%mm3 \n\t"
"movq %%mm0, %%mm4 \n\t"
"movq %%mm1, %%mm5 \n\t"
"pfadd %%mm2, %%mm0 \n\t"
"pfadd %%mm3, %%mm1 \n\t"
"pfsub %%mm2, %%mm4 \n\t"
"pfsub %%mm3, %%mm5 \n\t"
"movq %%mm0, %%mm2 \n\t"
"punpckldq %%mm5, %%mm6 \n\t"
"punpckhdq %%mm6, %%mm5 \n\t"
"movq %%mm4, %%mm3 \n\t"
"pxor %%mm7, %%mm5 \n\t"
"pfadd %%mm1, %%mm0 \n\t"
"pfadd %%mm5, %%mm4 \n\t"
"pfsub %%mm1, %%mm2 \n\t"
"pfsub %%mm5, %%mm3 \n\t"
"movq %%mm0, (%0,%1) \n\t"
"movq %%mm4, 8(%0,%1) \n\t"
"movq %%mm2, 16(%0,%1) \n\t"
"movq %%mm3, 24(%0,%1) \n\t"
"jg 1b \n\t"
:"+r"(i)
:"r"(z)
);
/* pass 2 .. ln-1 */
nblocks = 1 << (ln-3);
nloops = 1 << 2;
cptr = s->exptab1;
do {
p = z;
j = nblocks;
do {
i = nloops*8;
asm volatile(
"1: \n\t"
"sub $16, %0 \n\t"
"movq (%1,%0), %%mm0 \n\t"
"movq 8(%1,%0), %%mm1 \n\t"
"movq (%2,%0), %%mm2 \n\t"
"movq 8(%2,%0), %%mm3 \n\t"
"movq %%mm2, %%mm4 \n\t"
"movq %%mm3, %%mm5 \n\t"
"punpckldq %%mm2, %%mm2 \n\t"
"punpckldq %%mm3, %%mm3 \n\t"
"punpckhdq %%mm4, %%mm4 \n\t"
"punpckhdq %%mm5, %%mm5 \n\t"
"pfmul (%3,%0,2), %%mm2 \n\t" // cre*re cim*re
"pfmul 8(%3,%0,2), %%mm3 \n\t"
"pfmul 16(%3,%0,2), %%mm4 \n\t" // -cim*im cre*im
"pfmul 24(%3,%0,2), %%mm5 \n\t"
"pfadd %%mm2, %%mm4 \n\t" // cre*re-cim*im cim*re+cre*im
"pfadd %%mm3, %%mm5 \n\t"
"movq %%mm0, %%mm2 \n\t"
"movq %%mm1, %%mm3 \n\t"
"pfadd %%mm4, %%mm0 \n\t"
"pfadd %%mm5, %%mm1 \n\t"
"pfsub %%mm4, %%mm2 \n\t"
"pfsub %%mm5, %%mm3 \n\t"
"movq %%mm0, (%1,%0) \n\t"
"movq %%mm1, 8(%1,%0) \n\t"
"movq %%mm2, (%2,%0) \n\t"
"movq %%mm3, 8(%2,%0) \n\t"
"jg 1b \n\t"
:"+r"(i)
:"r"(p), "r"(p + nloops), "r"(cptr)
);
p += nloops*2;
} while (--j);
cptr += nloops*2;
nblocks >>= 1;
nloops <<= 1;
} while (nblocks != 0);