FFmpeg
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  unsigned y;
43 
44  __asm__("rev16 %0, %1" : "=r"(y) : "r"(x));
45  return y;
46 }
47 #endif
48 
49 #if AV_GCC_VERSION_AT_MOST(4,4)
50 #define av_bswap32 av_bswap32
51 static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
52 {
53  uint32_t y;
54 #if HAVE_ARMV6_INLINE
55  __asm__("rev %0, %1" : "=r"(y) : "r"(x));
56 #else
57  uint32_t t;
58  __asm__ ("eor %1, %2, %2, ror #16 \n\t"
59  "bic %1, %1, #0xFF0000 \n\t"
60  "mov %0, %2, ror #8 \n\t"
61  "eor %0, %0, %1, lsr #8 \n\t"
62  : "=r"(y), "=&r"(t) : "r"(x));
63 #endif /* HAVE_ARMV6_INLINE */
64  return y;
65 }
66 #endif /* AV_GCC_VERSION_AT_MOST(4,4) */
67 
68 #endif /* __ARMCC_VERSION */
69 
70 #endif /* AVUTIL_ARM_BSWAP_H */
av_const
#define av_const
Definition: attributes.h:84
av_bswap32
#define av_bswap32
Definition: bswap.h:33
av_bswap16
#define av_bswap16
Definition: bswap.h:31
attributes.h
av_always_inline
#define av_always_inline
Definition: attributes.h:49
__asm__
__asm__(".macro parse_r var r\n\t" "\\var = -1\n\t" _IFC_REG(0) _IFC_REG(1) _IFC_REG(2) _IFC_REG(3) _IFC_REG(4) _IFC_REG(5) _IFC_REG(6) _IFC_REG(7) _IFC_REG(8) _IFC_REG(9) _IFC_REG(10) _IFC_REG(11) _IFC_REG(12) _IFC_REG(13) _IFC_REG(14) _IFC_REG(15) _IFC_REG(16) _IFC_REG(17) _IFC_REG(18) _IFC_REG(19) _IFC_REG(20) _IFC_REG(21) _IFC_REG(22) _IFC_REG(23) _IFC_REG(24) _IFC_REG(25) _IFC_REG(26) _IFC_REG(27) _IFC_REG(28) _IFC_REG(29) _IFC_REG(30) _IFC_REG(31) ".iflt \\var\n\t" ".error \"Unable to parse register name \\r\"\n\t" ".endif\n\t" ".endm")