bswap.h
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1 /*
2  * This file is part of Libav.
3  *
4  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
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 !AV_GCC_VERSION_AT_LEAST(4,1)
32 #define av_bswap16 av_bswap16
33 static av_always_inline av_const unsigned av_bswap16(unsigned x)
34 {
35  __asm__("rorw $8, %w0" : "+r"(x));
36  return x;
37 }
38 #endif /* !AV_GCC_VERSION_AT_LEAST(4,1) */
39 
40 #if !AV_GCC_VERSION_AT_LEAST(4,5)
41 #define av_bswap32 av_bswap32
42 static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
43 {
44  __asm__("bswap %0" : "+r" (x));
45  return x;
46 }
47 
48 #if ARCH_X86_64
49 #define av_bswap64 av_bswap64
50 static inline uint64_t av_const av_bswap64(uint64_t x)
51 {
52  __asm__("bswap %0": "=r" (x) : "0" (x));
53  return x;
54 }
55 #endif
56 #endif /* !AV_GCC_VERSION_AT_LEAST(4,5) */
57 
58 #endif /* AVUTIL_X86_BSWAP_H */