1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
/*****************************************************************************
* bytes_swap.h: fast routines to swap bytes order.
*****************************************************************************
* Copyright (C) 1998, 1999, 2000 VideoLAN
* $Id: bytes_swap.h,v 1.1 2001/11/25 22:52:21 gbazin Exp $
*
* Authors: This code was borrowed from the GNU C Library.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
*****************************************************************************/
/* Swap bytes in 16 bit value. */
#define __bswap_constant_16(x) \
((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
#if defined __GNUC__ && __GNUC__ >= 2
# define __bswap_16(x) \
(__extension__ \
({ register unsigned short int __v; \
if (__builtin_constant_p (x)) \
__v = __bswap_constant_16 (x); \
else \
__asm__ __volatile__ ("rorw $8, %w0" \
: "=r" (__v) \
: "0" ((unsigned short int) (x)) \
: "cc"); \
__v; }))
#else
/* This is better than nothing. */
# define __bswap_16(x) __bswap_constant_16 (x)
#endif
/* Swap bytes in 32 bit value. */
#define __bswap_constant_32(x) \
((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
(((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
#if defined __GNUC__ && __GNUC__ >= 2
/* To swap the bytes in a word the i486 processors and up provide the
`bswap' opcode. On i386 we have to use three instructions. */
# if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__
# define __bswap_32(x) \
(__extension__ \
({ register unsigned int __v; \
if (__builtin_constant_p (x)) \
__v = __bswap_constant_32 (x); \
else \
__asm__ __volatile__ ("rorw $8, %w0;" \
"rorl $16, %0;" \
"rorw $8, %w0" \
: "=r" (__v) \
: "0" ((unsigned int) (x)) \
: "cc"); \
__v; }))
# else
# define __bswap_32(x) \
(__extension__ \
({ register unsigned int __v; \
if (__builtin_constant_p (x)) \
__v = __bswap_constant_32 (x); \
else \
__asm__ __volatile__ ("bswap %0" \
: "=r" (__v) \
: "0" ((unsigned int) (x))); \
__v; }))
# endif
#else
# define __bswap_32(x) __bswap_constant_32 (x)
#endif
#if defined __GNUC__ && __GNUC__ >= 2
/* Swap bytes in 64 bit value. */
#define __bswap_constant_64(x) \
((((x) & 0xff00000000000000ull) >> 56) \
| (((x) & 0x00ff000000000000ull) >> 40) \
| (((x) & 0x0000ff0000000000ull) >> 24) \
| (((x) & 0x000000ff00000000ull) >> 8) \
| (((x) & 0x00000000ff000000ull) << 8) \
| (((x) & 0x0000000000ff0000ull) << 24) \
| (((x) & 0x000000000000ff00ull) << 40) \
| (((x) & 0x00000000000000ffull) << 56))
# define __bswap_64(x) \
(__extension__ \
({ union { __extension__ unsigned long long int __ll; \
unsigned long int __l[2]; } __w, __r; \
if (__builtin_constant_p (x)) \
__r.__ll = __bswap_constant_64 (x); \
else \
{ \
__w.__ll = (x); \
__r.__l[0] = __bswap_32 (__w.__l[1]); \
__r.__l[1] = __bswap_32 (__w.__l[0]); \
} \
__r.__ll; }))
#endif
|
