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620e6e1487
There are no particular reasons to force the compiler to use the same register as output and input operand. This forces an extra MOV instruction if the input value needs to be reused after the swap. In most cases, this makes no differences, as the compiler will seleect the same register for both operands either way. Signed-off-by: Martin Storsjö <martin@martin.st>
71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
/*
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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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#ifndef AVUTIL_ARM_BSWAP_H
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#define AVUTIL_ARM_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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#ifdef __ARMCC_VERSION
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#if HAVE_ARMV6
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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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return __rev(x);
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}
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#endif /* HAVE_ARMV6 */
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#elif HAVE_INLINE_ASM
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#if HAVE_ARMV6_INLINE
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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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unsigned y;
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__asm__("rev16 %0, %1" : "=r"(y) : "r"(x));
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return y;
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}
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#endif
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#if AV_GCC_VERSION_AT_MOST(4,4)
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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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uint32_t y;
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#if HAVE_ARMV6_INLINE
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__asm__("rev %0, %1" : "=r"(y) : "r"(x));
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#else
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uint32_t t;
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__asm__ ("eor %1, %2, %2, ror #16 \n\t"
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"bic %1, %1, #0xFF0000 \n\t"
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"mov %0, %2, ror #8 \n\t"
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"eor %0, %0, %1, lsr #8 \n\t"
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: "=r"(y), "=&r"(t) : "r"(x));
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#endif /* HAVE_ARMV6_INLINE */
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return y;
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}
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#endif /* AV_GCC_VERSION_AT_MOST(4,4) */
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#endif /* __ARMCC_VERSION */
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#endif /* AVUTIL_ARM_BSWAP_H */
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