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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>
84 lines
2.1 KiB
C
84 lines
2.1 KiB
C
/*
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* TAK decoder
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* Copyright (c) 2015 Paul B Mahol
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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 "libavutil/attributes.h"
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#include "takdsp.h"
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#include "config.h"
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static void decorrelate_ls(int32_t *p1, int32_t *p2, int length)
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{
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int i;
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for (i = 0; i < length; i++) {
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int32_t a = p1[i];
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int32_t b = p2[i];
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p2[i] = a + b;
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}
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}
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static void decorrelate_sr(int32_t *p1, int32_t *p2, int length)
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{
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int i;
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for (i = 0; i < length; i++) {
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int32_t a = p1[i];
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int32_t b = p2[i];
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p1[i] = b - a;
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}
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}
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static void decorrelate_sm(int32_t *p1, int32_t *p2, int length)
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{
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int i;
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for (i = 0; i < length; i++) {
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int32_t a = p1[i];
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int32_t b = p2[i];
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a -= b >> 1;
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p1[i] = a;
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p2[i] = a + b;
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}
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}
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static void decorrelate_sf(int32_t *p1, int32_t *p2, int length, int dshift, int dfactor)
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{
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int i;
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for (i = 0; i < length; i++) {
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int32_t a = p1[i];
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int32_t b = p2[i];
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b = (unsigned)((int)(dfactor * (unsigned)(b >> dshift) + 128) >> 8) << dshift;
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p1[i] = b - a;
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}
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}
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av_cold void ff_takdsp_init(TAKDSPContext *c)
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{
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c->decorrelate_ls = decorrelate_ls;
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c->decorrelate_sr = decorrelate_sr;
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c->decorrelate_sm = decorrelate_sm;
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c->decorrelate_sf = decorrelate_sf;
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#if ARCH_X86
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ff_takdsp_init_x86(c);
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#endif
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}
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