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40e6575aa3
This is more spec-compliant because it does not rely on dead-code elimination by the compiler. Especially MSVC has problems with this, as can be seen in https://ffmpeg.org/pipermail/ffmpeg-devel/2022-May/296373.html or https://ffmpeg.org/pipermail/ffmpeg-devel/2022-May/297022.html This commit does not eliminate every instance where we rely on dead code elimination: It only tackles branching to the initialization of arch-specific dsp code, not e.g. all uses of CONFIG_ and HAVE_ checks. But maybe it is already enough to compile FFmpeg with MSVC with whole-programm-optimizations enabled (if one does not disable too many components). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
114 lines
3.5 KiB
C
114 lines
3.5 KiB
C
/*
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* Copyright (c) 2011 Mans Rullgard
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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/attributes.h"
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#include "libavutil/thread.h"
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#include "mpegaudio.h"
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#include "mpegaudiodsp.h"
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#include "dct.h"
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#include "dct32.h"
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static AVOnce mpadsp_table_init = AV_ONCE_INIT;
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static av_cold void mpadsp_init_tabs(void)
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{
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int i, j;
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/* compute mdct windows */
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for (i = 0; i < 36; i++) {
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for (j = 0; j < 4; j++) {
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double d;
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if (j == 2 && i % 3 != 1)
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continue;
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d = sin(M_PI * (i + 0.5) / 36.0);
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if (j == 1) {
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if (i >= 30) d = 0;
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else if (i >= 24) d = sin(M_PI * (i - 18 + 0.5) / 12.0);
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else if (i >= 18) d = 1;
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} else if (j == 3) {
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if (i < 6) d = 0;
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else if (i < 12) d = sin(M_PI * (i - 6 + 0.5) / 12.0);
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else if (i < 18) d = 1;
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}
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//merge last stage of imdct into the window coefficients
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d *= 0.5 * IMDCT_SCALAR / cos(M_PI * (2 * i + 19) / 72);
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if (j == 2) {
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ff_mdct_win_float[j][i/3] = d / (1 << 5);
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ff_mdct_win_fixed[j][i/3] = d / (1 << 5) * (1LL << 32) + 0.5;
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} else {
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int idx = i < 18 ? i : i + (MDCT_BUF_SIZE/2 - 18);
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ff_mdct_win_float[j][idx] = d / (1 << 5);
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ff_mdct_win_fixed[j][idx] = d / (1 << 5) * (1LL << 32) + 0.5;
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}
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}
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}
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/* NOTE: we do frequency inversion after the MDCT by changing
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the sign of the right window coefs */
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for (j = 0; j < 4; j++) {
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for (i = 0; i < MDCT_BUF_SIZE; i += 2) {
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ff_mdct_win_float[j + 4][i ] = ff_mdct_win_float[j][i ];
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ff_mdct_win_float[j + 4][i + 1] = -ff_mdct_win_float[j][i + 1];
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ff_mdct_win_fixed[j + 4][i ] = ff_mdct_win_fixed[j][i ];
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ff_mdct_win_fixed[j + 4][i + 1] = -ff_mdct_win_fixed[j][i + 1];
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}
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}
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#if ARCH_X86
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ff_mpadsp_init_x86_tabs();
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#endif
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}
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av_cold void ff_mpadsp_init(MPADSPContext *s)
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{
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DCTContext dct;
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ff_dct_init(&dct, 5, DCT_II);
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ff_thread_once(&mpadsp_table_init, &mpadsp_init_tabs);
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s->apply_window_float = ff_mpadsp_apply_window_float;
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s->apply_window_fixed = ff_mpadsp_apply_window_fixed;
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s->dct32_float = dct.dct32;
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s->dct32_fixed = ff_dct32_fixed;
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s->imdct36_blocks_float = ff_imdct36_blocks_float;
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s->imdct36_blocks_fixed = ff_imdct36_blocks_fixed;
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#if ARCH_AARCH64
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ff_mpadsp_init_aarch64(s);
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#elif ARCH_ARM
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ff_mpadsp_init_arm(s);
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#elif ARCH_PPC
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ff_mpadsp_init_ppc(s);
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#elif ARCH_X86
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ff_mpadsp_init_x86(s);
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#endif
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#if HAVE_MIPSFPU
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ff_mpadsp_init_mipsfpu(s);
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#endif
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#if HAVE_MIPSDSP
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ff_mpadsp_init_mipsdsp(s);
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#endif
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}
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