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FFmpeg/libavutil/x86/bswap.h
Jason Garrett-Glaser 15919ee48f bswap: use native types for av_bwap16().
This prevents a call to bytestream_get_be16() using a movzwl both before
and after the ror instruction, which is obviously inefficient. Arm uses
the same trick also.

Sintel decoding goes from (avg+SD) 9.856 +/- 0.003 to 9.797 +/- 0.003 sec.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
2011-04-22 20:05:48 -04:00

62 lines
1.6 KiB
C

/*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* byte swapping routines
*/
#ifndef AVUTIL_X86_BSWAP_H
#define AVUTIL_X86_BSWAP_H
#include <stdint.h>
#include "config.h"
#include "libavutil/attributes.h"
#define av_bswap16 av_bswap16
static av_always_inline av_const unsigned av_bswap16(unsigned x)
{
__asm__("rorw $8, %w0" : "+r"(x));
return x;
}
#define av_bswap32 av_bswap32
static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
{
#if HAVE_BSWAP
__asm__("bswap %0" : "+r" (x));
#else
__asm__("rorw $8, %w0 \n\t"
"rorl $16, %0 \n\t"
"rorw $8, %w0"
: "+r"(x));
#endif
return x;
}
#if ARCH_X86_64
#define av_bswap64 av_bswap64
static inline uint64_t av_const av_bswap64(uint64_t x)
{
__asm__("bswap %0": "=r" (x) : "0" (x));
return x;
}
#endif
#endif /* AVUTIL_X86_BSWAP_H */