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https://github.com/FFmpeg/FFmpeg.git
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e1120b1c54
c: 1802 decicycles in fft15,16774635 runs, 2581 skips avx: 865 decicycles in fft15,16776378 runs, 838 skips Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
96 lines
3.0 KiB
C
96 lines
3.0 KiB
C
/*
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* SIMD optimized non-power-of-two MDCT functions
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*
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* Copyright (C) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "config.h"
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#include "libavutil/x86/cpu.h"
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#include "libavcodec/mdct15.h"
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void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
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static void perm_twiddles(MDCT15Context *s)
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{
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int k;
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FFTComplex exp_5point[4];
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FFTComplex tmp[21], tmp2[30];
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memcpy(tmp, s->exptab, sizeof(FFTComplex)*21);
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/* 15-point FFT twiddles */
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for (k = 0; k < 5; k++) {
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tmp2[6*k + 0] = tmp[k + 0];
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tmp2[6*k + 2] = tmp[k + 5];
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tmp2[6*k + 4] = tmp[k + 10];
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tmp2[6*k + 1] = tmp[2 * (k + 0)];
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tmp2[6*k + 3] = tmp[2 * (k + 5)];
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tmp2[6*k + 5] = tmp[2 * k + 5 ];
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}
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for (k = 0; k < 6; k++) {
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FFTComplex ac_exp[] = {
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{ tmp2[6*1 + k].re, tmp2[6*1 + k].re },
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{ tmp2[6*2 + k].re, tmp2[6*2 + k].re },
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{ tmp2[6*3 + k].re, tmp2[6*3 + k].re },
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{ tmp2[6*4 + k].re, tmp2[6*4 + k].re },
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{ tmp2[6*1 + k].im, -tmp2[6*1 + k].im },
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{ tmp2[6*2 + k].im, -tmp2[6*2 + k].im },
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{ tmp2[6*3 + k].im, -tmp2[6*3 + k].im },
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{ tmp2[6*4 + k].im, -tmp2[6*4 + k].im },
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};
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memcpy(s->exptab + 8*k, ac_exp, 8*sizeof(FFTComplex));
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}
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/* Specialcase when k = 0 */
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for (k = 0; k < 3; k++) {
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FFTComplex dc_exp[] = {
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{ tmp2[2*k + 0].re, -tmp2[2*k + 0].im },
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{ tmp2[2*k + 0].im, tmp2[2*k + 0].re },
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{ tmp2[2*k + 1].re, -tmp2[2*k + 1].im },
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{ tmp2[2*k + 1].im, tmp2[2*k + 1].re },
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};
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memcpy(s->exptab + 8*6 + 4*k, dc_exp, 4*sizeof(FFTComplex));
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}
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/* 5-point FFT twiddles */
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exp_5point[0].re = exp_5point[0].im = tmp[19].re;
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exp_5point[1].re = exp_5point[1].im = tmp[19].im;
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exp_5point[2].re = exp_5point[2].im = tmp[20].re;
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exp_5point[3].re = exp_5point[3].im = tmp[20].im;
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memcpy(s->exptab + 8*6 + 4*3, exp_5point, 4*sizeof(FFTComplex));
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}
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av_cold void ff_mdct15_init_x86(MDCT15Context *s)
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{
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int adjust_twiddles = 0;
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int cpu_flags = av_get_cpu_flags();
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if (ARCH_X86_64 && EXTERNAL_AVX(cpu_flags)) {
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s->fft15 = ff_fft15_avx;
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adjust_twiddles = 1;
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}
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if (adjust_twiddles)
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perm_twiddles(s);
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}
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