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bswap.h
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 /**
20  * @file
21  * byte swapping routines
22  */
23 
24 #ifndef AVUTIL_X86_BSWAP_H
25 #define AVUTIL_X86_BSWAP_H
26 
27 #include <stdint.h>
28 #include "config.h"
29 #include "libavutil/attributes.h"
30 
31 #if HAVE_INLINE_ASM
32 
33 #if !AV_GCC_VERSION_AT_LEAST(4,1)
34 #define av_bswap16 av_bswap16
35 static av_always_inline av_const unsigned av_bswap16(unsigned x)
36 {
37  __asm__("rorw $8, %w0" : "+r"(x));
38  return x;
39 }
40 #endif /* !AV_GCC_VERSION_AT_LEAST(4,1) */
41 
42 #if !AV_GCC_VERSION_AT_LEAST(4,5)
43 #define av_bswap32 av_bswap32
44 static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
45 {
46  __asm__("bswap %0" : "+r" (x));
47  return x;
48 }
49 
50 #if ARCH_X86_64
51 #define av_bswap64 av_bswap64
52 static inline uint64_t av_const av_bswap64(uint64_t x)
53 {
54  __asm__("bswap %0": "=r" (x) : "0" (x));
55  return x;
56 }
57 #endif
58 #endif /* !AV_GCC_VERSION_AT_LEAST(4,5) */
59 
60 #endif /* HAVE_INLINE_ASM */
61 #endif /* AVUTIL_X86_BSWAP_H */