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FFmpeg/libavcodec/bswapdsp.c
Andreas Rheinhardt 40e6575aa3 all: Replace if (ARCH_FOO) checks by #if ARCH_FOO
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>
2022-06-15 04:56:37 +02:00

58 lines
1.7 KiB
C

/*
* 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 <stdint.h>
#include "libavutil/attributes.h"
#include "libavutil/bswap.h"
#include "bswapdsp.h"
static void bswap_buf(uint32_t *dst, const uint32_t *src, int w)
{
int i;
for (i = 0; i + 8 <= w; i += 8) {
dst[i + 0] = av_bswap32(src[i + 0]);
dst[i + 1] = av_bswap32(src[i + 1]);
dst[i + 2] = av_bswap32(src[i + 2]);
dst[i + 3] = av_bswap32(src[i + 3]);
dst[i + 4] = av_bswap32(src[i + 4]);
dst[i + 5] = av_bswap32(src[i + 5]);
dst[i + 6] = av_bswap32(src[i + 6]);
dst[i + 7] = av_bswap32(src[i + 7]);
}
for (; i < w; i++)
dst[i + 0] = av_bswap32(src[i + 0]);
}
static void bswap16_buf(uint16_t *dst, const uint16_t *src, int len)
{
while (len--)
*dst++ = av_bswap16(*src++);
}
av_cold void ff_bswapdsp_init(BswapDSPContext *c)
{
c->bswap_buf = bswap_buf;
c->bswap16_buf = bswap16_buf;
#if ARCH_X86
ff_bswapdsp_init_x86(c);
#endif
}