[FFmpeg-devel] [PATCH] faster SSE FFT
Loren Merritt
lorenm
Sat Feb 12 15:02:05 CET 2011
Factor a shuffle out of the inner loop and merge it into fft_permute.
6% faster SSE FFT on Conroe, 2.5% on Penryn.
--Loren Merritt
-------------- next part --------------
>From 64d5047455d7bfc785628efdf08883983396446b Mon Sep 17 00:00:00 2001
From: Loren Merritt <lorenm at u.washington.edu>
Date: Sat, 12 Feb 2011 11:48:16 +0000
Subject: [PATCH] FFT: factor a shuffle out of the inner loop and merge it into fft_permute.
6% faster SSE FFT on Conroe, 2.5% on Penryn.
---
libavcodec/arm/fft_init_arm.c | 2 +-
libavcodec/fft.c | 9 ++++-
libavcodec/fft.h | 5 ++-
libavcodec/mdct.c | 4 +-
libavcodec/x86/fft.c | 1 +
libavcodec/x86/fft_mmx.asm | 62 ++++++++++++++++++++---------------------
6 files changed, 45 insertions(+), 38 deletions(-)
diff --git a/libavcodec/arm/fft_init_arm.c b/libavcodec/arm/fft_init_arm.c
index bde1240..df29b4a 100644
--- a/libavcodec/arm/fft_init_arm.c
+++ b/libavcodec/arm/fft_init_arm.c
@@ -44,7 +44,7 @@ av_cold void ff_fft_init_arm(FFTContext *s)
s->imdct_calc = ff_imdct_calc_neon;
s->imdct_half = ff_imdct_half_neon;
s->mdct_calc = ff_mdct_calc_neon;
- s->permutation = FF_MDCT_PERM_INTERLEAVE;
+ s->mdct_permutation = FF_MDCT_PERM_INTERLEAVE;
}
}
diff --git a/libavcodec/fft.c b/libavcodec/fft.c
index 3fd4d27..eade76a 100644
--- a/libavcodec/fft.c
+++ b/libavcodec/fft.c
@@ -97,6 +97,7 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
if (!s->tmp_buf)
goto fail;
s->inverse = inverse;
+ s->fft_permutation = FF_FFT_PERM_DEFAULT;
s->fft_permute = ff_fft_permute_c;
s->fft_calc = ff_fft_calc_c;
@@ -113,8 +114,12 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
for(j=4; j<=nbits; j++) {
ff_init_ff_cos_tabs(j);
}
- for(i=0; i<n; i++)
- s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = i;
+ for(i=0; i<n; i++) {
+ int j = i;
+ if (s->fft_permutation == FF_FFT_PERM_SWAP_LSBS)
+ j = (j&~3) | ((j>>1)&1) | ((j<<1)&2);
+ s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = j;
+ }
return 0;
fail:
diff --git a/libavcodec/fft.h b/libavcodec/fft.h
index 37cbfbf..58a7f30 100644
--- a/libavcodec/fft.h
+++ b/libavcodec/fft.h
@@ -44,7 +44,10 @@ struct FFTContext {
void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
- int permutation;
+ int fft_permutation;
+#define FF_FFT_PERM_DEFAULT 0
+#define FF_FFT_PERM_SWAP_LSBS 1
+ int mdct_permutation;
#define FF_MDCT_PERM_NONE 0
#define FF_MDCT_PERM_INTERLEAVE 1
};
diff --git a/libavcodec/mdct.c b/libavcodec/mdct.c
index c511188..819f618 100644
--- a/libavcodec/mdct.c
+++ b/libavcodec/mdct.c
@@ -71,7 +71,7 @@ av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
s->mdct_bits = nbits;
s->mdct_size = n;
n4 = n >> 2;
- s->permutation = FF_MDCT_PERM_NONE;
+ s->mdct_permutation = FF_MDCT_PERM_NONE;
if (ff_fft_init(s, s->mdct_bits - 2, inverse) < 0)
goto fail;
@@ -80,7 +80,7 @@ av_cold int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale)
if (!s->tcos)
goto fail;
- switch (s->permutation) {
+ switch (s->mdct_permutation) {
case FF_MDCT_PERM_NONE:
s->tsin = s->tcos + n4;
tstep = 1;
diff --git a/libavcodec/x86/fft.c b/libavcodec/x86/fft.c
index 771b1e6..5ca341d 100644
--- a/libavcodec/x86/fft.c
+++ b/libavcodec/x86/fft.c
@@ -30,6 +30,7 @@ av_cold void ff_fft_init_mmx(FFTContext *s)
s->imdct_half = ff_imdct_half_sse;
s->fft_permute = ff_fft_permute_sse;
s->fft_calc = ff_fft_calc_sse;
+ s->fft_permutation = FF_FFT_PERM_SWAP_LSBS;
} else if (has_vectors & AV_CPU_FLAG_3DNOWEXT && HAVE_AMD3DNOWEXT) {
/* 3DNowEx for K7 */
s->imdct_calc = ff_imdct_calc_3dn2;
diff --git a/libavcodec/x86/fft_mmx.asm b/libavcodec/x86/fft_mmx.asm
index 1dcd629..68e20df 100644
--- a/libavcodec/x86/fft_mmx.asm
+++ b/libavcodec/x86/fft_mmx.asm
@@ -51,6 +51,7 @@ SECTION_RODATA
%define M_SQRT1_2 0.70710678118654752440
ps_root2: times 4 dd M_SQRT1_2
ps_root2mppm: dd -M_SQRT1_2, M_SQRT1_2, M_SQRT1_2, -M_SQRT1_2
+ps_p1p1m1p1: dd 0, 0, 1<<31, 0
ps_m1p1: dd 1<<31, 0
%assign i 16
@@ -95,54 +96,51 @@ section .text align=16
SWAP %3, %6
%endmacro
-; in: %1={r0,i0,r1,i1} %2={r2,i2,r3,i3}
+; in: %1={r0,i0,r2,i2} %2={r1,i1,r3,i3}
; out: %1={r0,r1,r2,r3} %2={i0,i1,i2,i3}
%macro T4_SSE 3
mova %3, %1
- shufps %1, %2, 0x64 ; {r0,i0,r3,i2}
- shufps %3, %2, 0xce ; {r1,i1,r2,i3}
+ addps %1, %2 ; {t1,t2,t6,t5}
+ subps %3, %2 ; {t3,t4,-t8,t7}
+ xorps %3, [ps_p1p1m1p1]
mova %2, %1
- addps %1, %3 ; {t1,t2,t6,t5}
- subps %2, %3 ; {t3,t4,t8,t7}
+ shufps %1, %3, 0x44 ; {t1,t2,t3,t4}
+ shufps %2, %3, 0xbe ; {t6,t5,t7,t8}
mova %3, %1
- shufps %1, %2, 0x44 ; {t1,t2,t3,t4}
- shufps %3, %2, 0xbe ; {t6,t5,t7,t8}
+ addps %1, %2 ; {r0,i0,r1,i1}
+ subps %3, %2 ; {r2,i2,r3,i3}
mova %2, %1
- addps %1, %3 ; {r0,i0,r1,i1}
- subps %2, %3 ; {r2,i2,r3,i3}
- mova %3, %1
- shufps %1, %2, 0x88 ; {r0,r1,r2,r3}
- shufps %3, %2, 0xdd ; {i0,i1,i2,i3}
- SWAP %2, %3
+ shufps %1, %3, 0x88 ; {r0,r1,r2,r3}
+ shufps %2, %3, 0xdd ; {i0,i1,i2,i3}
%endmacro
-%macro T8_SSE 6 ; r0,i0,r1,i1,t0,t1
- mova %5, %3
- shufps %3, %4, 0x44 ; {r4,i4,r6,i6}
- shufps %5, %4, 0xee ; {r5,i5,r7,i7}
+; in: %1={r0,r1,r2,r3} %2={i0,i1,i2,i3} %3={r4,i4,r6,i6} %4={r5,i5,r7,i7}
+; out: %1={r0,r1,r2,r3} %2={i0,i1,i2,i3} %1={r4,r5,r6,r7} %2={i4,i5,i6,i7}
+%macro T8_SSE 6
mova %6, %3
- subps %3, %5 ; {r5,i5,r7,i7}
- addps %6, %5 ; {t1,t2,t3,t4}
- mova %5, %3
- shufps %5, %5, 0xb1 ; {i5,r5,i7,r7}
+ subps %3, %4 ; {r5,i5,r7,i7}
+ addps %6, %4 ; {t1,t2,t3,t4}
+ mova %4, %3
+ shufps %4, %4, 0xb1 ; {i5,r5,i7,r7}
mulps %3, [ps_root2mppm] ; {-r5,i5,r7,-i7}
- mulps %5, [ps_root2]
- addps %3, %5 ; {t8,t7,ta,t9}
- mova %5, %6
+ mulps %4, [ps_root2]
+ addps %3, %4 ; {t8,t7,ta,t9}
+ mova %4, %6
shufps %6, %3, 0x36 ; {t3,t2,t9,t8}
- shufps %5, %3, 0x9c ; {t1,t4,t7,ta}
+ shufps %4, %3, 0x9c ; {t1,t4,t7,ta}
mova %3, %6
- addps %6, %5 ; {t1,t2,t9,ta}
- subps %3, %5 ; {t6,t5,tc,tb}
- mova %5, %6
+ addps %6, %4 ; {t1,t2,t9,ta}
+ subps %3, %4 ; {t6,t5,tc,tb}
+ mova %4, %6
shufps %6, %3, 0xd8 ; {t1,t9,t5,tb}
- shufps %5, %3, 0x8d ; {t2,ta,t6,tc}
+ shufps %4, %3, 0x8d ; {t2,ta,t6,tc}
mova %3, %1
- mova %4, %2
+ mova %5, %2
addps %1, %6 ; {r0,r1,r2,r3}
- addps %2, %5 ; {i0,i1,i2,i3}
+ addps %2, %4 ; {i0,i1,i2,i3}
subps %3, %6 ; {r4,r5,r6,r7}
- subps %4, %5 ; {i4,i5,i6,i7}
+ subps %5, %4 ; {i4,i5,i6,i7}
+ SWAP %4, %5
%endmacro
; scheduled for cpu-bound sizes
--
1.7.0.4
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