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FFmpeg/libavcodec/x86/mdct15_init.c
Rostislav Pehlivanov 29eb1c51d7 mdct15: simplify x86 exptab permutation
Removes an unneeded copy and does the 5-point permute in-place.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
2018-05-07 23:44:40 +01:00

100 lines
3.3 KiB
C

/*
* SIMD optimized non-power-of-two MDCT functions
*
* Copyright (C) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include "libavutil/x86/cpu.h"
#include "libavcodec/mdct15.h"
void ff_mdct15_postreindex_sse3(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
void ff_mdct15_postreindex_avx2(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
static void perm_twiddles(MDCT15Context *s)
{
int k;
FFTComplex tmp[30];
/* 5-point FFT twiddles */
s->exptab[60].re = s->exptab[60].im = s->exptab[19].re;
s->exptab[61].re = s->exptab[61].im = s->exptab[19].im;
s->exptab[62].re = s->exptab[62].im = s->exptab[20].re;
s->exptab[63].re = s->exptab[63].im = s->exptab[20].im;
/* 15-point FFT twiddles */
for (k = 0; k < 5; k++) {
tmp[6*k + 0] = s->exptab[k + 0];
tmp[6*k + 2] = s->exptab[k + 5];
tmp[6*k + 4] = s->exptab[k + 10];
tmp[6*k + 1] = s->exptab[2 * (k + 0)];
tmp[6*k + 3] = s->exptab[2 * (k + 5)];
tmp[6*k + 5] = s->exptab[2 * k + 5 ];
}
for (k = 0; k < 6; k++) {
FFTComplex ac_exp[] = {
{ tmp[6*1 + k].re, tmp[6*1 + k].re },
{ tmp[6*2 + k].re, tmp[6*2 + k].re },
{ tmp[6*3 + k].re, tmp[6*3 + k].re },
{ tmp[6*4 + k].re, tmp[6*4 + k].re },
{ tmp[6*1 + k].im, -tmp[6*1 + k].im },
{ tmp[6*2 + k].im, -tmp[6*2 + k].im },
{ tmp[6*3 + k].im, -tmp[6*3 + k].im },
{ tmp[6*4 + k].im, -tmp[6*4 + k].im },
};
memcpy(s->exptab + 8*k, ac_exp, 8*sizeof(FFTComplex));
}
/* Specialcase when k = 0 */
for (k = 0; k < 3; k++) {
FFTComplex dc_exp[] = {
{ tmp[2*k + 0].re, -tmp[2*k + 0].im },
{ tmp[2*k + 0].im, tmp[2*k + 0].re },
{ tmp[2*k + 1].re, -tmp[2*k + 1].im },
{ tmp[2*k + 1].im, tmp[2*k + 1].re },
};
memcpy(s->exptab + 8*6 + 4*k, dc_exp, 4*sizeof(FFTComplex));
}
}
av_cold void ff_mdct15_init_x86(MDCT15Context *s)
{
int adjust_twiddles = 0;
int cpu_flags = av_get_cpu_flags();
if (EXTERNAL_SSE3(cpu_flags))
s->postreindex = ff_mdct15_postreindex_sse3;
if (ARCH_X86_64 && EXTERNAL_AVX(cpu_flags)) {
s->fft15 = ff_fft15_avx;
adjust_twiddles = 1;
}
if (ARCH_X86_64 && EXTERNAL_AVX2_FAST(cpu_flags))
s->postreindex = ff_mdct15_postreindex_avx2;
if (adjust_twiddles)
perm_twiddles(s);
}