f64c2e710f
With these changes, gcc 4.5 and later recognise it as a bswap and use the proper instructions on ARM and x86. On x86, the 16-bit bswap is recognised from gcc 4.1. Signed-off-by: Mans Rullgard <mans@mansr.com>
66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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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/**
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* @file
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* byte swapping routines
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*/
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#ifndef AVUTIL_X86_BSWAP_H
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#define AVUTIL_X86_BSWAP_H
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#include <stdint.h>
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#include "config.h"
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#include "libavutil/attributes.h"
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#if !AV_GCC_VERSION_AT_LEAST(4,1)
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#define av_bswap16 av_bswap16
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static av_always_inline av_const unsigned av_bswap16(unsigned x)
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{
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__asm__("rorw $8, %w0" : "+r"(x));
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return x;
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}
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#endif /* !AV_GCC_VERSION_AT_LEAST(4,1) */
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#if !AV_GCC_VERSION_AT_LEAST(4,5)
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#define av_bswap32 av_bswap32
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static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
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{
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#if HAVE_BSWAP
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__asm__("bswap %0" : "+r" (x));
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#else
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__asm__("rorw $8, %w0 \n\t"
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"rorl $16, %0 \n\t"
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"rorw $8, %w0"
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: "+r"(x));
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#endif
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return x;
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}
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#if ARCH_X86_64
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#define av_bswap64 av_bswap64
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static inline uint64_t av_const av_bswap64(uint64_t x)
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{
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__asm__("bswap %0": "=r" (x) : "0" (x));
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return x;
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}
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#endif
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#endif /* !AV_GCC_VERSION_AT_LEAST(4,5) */
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#endif /* AVUTIL_X86_BSWAP_H */
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