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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 #ifndef AVUTIL_ARM_BSWAP_H
20 #define AVUTIL_ARM_BSWAP_H
21 
22 #include <stdint.h>
23 #include "config.h"
24 #include "libavutil/attributes.h"
25 
26 #ifdef __ARMCC_VERSION
27 
28 #if HAVE_ARMV6
29 #define av_bswap32 av_bswap32
30 static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
31 {
32  return __rev(x);
33 }
34 #endif /* HAVE_ARMV6 */
35 
36 #elif HAVE_INLINE_ASM
37 
38 #if HAVE_ARMV6_INLINE
39 #define av_bswap16 av_bswap16
40 static av_always_inline av_const unsigned av_bswap16(unsigned x)
41 {
42  __asm__("rev16 %0, %0" : "+r"(x));
43  return x;
44 }
45 #endif
46 
47 #if !AV_GCC_VERSION_AT_LEAST(4,5)
48 #define av_bswap32 av_bswap32
49 static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
50 {
51 #if HAVE_ARMV6_INLINE
52  __asm__("rev %0, %0" : "+r"(x));
53 #else
54  uint32_t t;
55  __asm__ ("eor %1, %0, %0, ror #16 \n\t"
56  "bic %1, %1, #0xFF0000 \n\t"
57  "mov %0, %0, ror #8 \n\t"
58  "eor %0, %0, %1, lsr #8 \n\t"
59  : "+r"(x), "=&r"(t));
60 #endif /* HAVE_ARMV6_INLINE */
61  return x;
62 }
63 #endif /* !AV_GCC_VERSION_AT_LEAST(4,5) */
64 
65 #endif /* __ARMCC_VERSION */
66 
67 #endif /* AVUTIL_ARM_BSWAP_H */