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1 : /* Macros to swap the order of bytes in integer values.
2 : Copyright (C) 1997-2015 Free Software Foundation, Inc.
3 : This file is part of the GNU C Library.
4 :
5 : The GNU C Library is free software; you can redistribute it and/or
6 : modify it under the terms of the GNU Lesser General Public
7 : License as published by the Free Software Foundation; either
8 : version 2.1 of the License, or (at your option) any later version.
9 :
10 : The GNU C Library is distributed in the hope that it will be useful,
11 : but WITHOUT ANY WARRANTY; without even the implied warranty of
12 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 : Lesser General Public License for more details.
14 :
15 : You should have received a copy of the GNU Lesser General Public
16 : License along with the GNU C Library; if not, see
17 : <http://www.gnu.org/licenses/>. */
18 :
19 : #if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
20 : # error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
21 : #endif
22 :
23 : #ifndef _BITS_BYTESWAP_H
24 : #define _BITS_BYTESWAP_H 1
25 :
26 : #include <features.h>
27 : #include <bits/types.h>
28 : #include <bits/wordsize.h>
29 :
30 : /* Swap bytes in 16 bit value. */
31 : #define __bswap_constant_16(x) \
32 : ((unsigned short int) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
33 :
34 : /* Get __bswap_16. */
35 : #include <bits/byteswap-16.h>
36 :
37 : /* Swap bytes in 32 bit value. */
38 : #define __bswap_constant_32(x) \
39 : ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
40 : (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
41 :
42 : #ifdef __GNUC__
43 : # if __GNUC_PREREQ (4, 3)
44 : static __inline unsigned int
45 3 : __bswap_32 (unsigned int __bsx)
46 : {
47 3 : return __builtin_bswap32 (__bsx);
48 : }
49 : # elif __GNUC__ >= 2
50 : # if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__ \
51 : || defined __pentiumpro__ || defined __pentium4__ \
52 : || defined __k8__ || defined __athlon__ \
53 : || defined __k6__ || defined __nocona__ \
54 : || defined __core2__ || defined __geode__ \
55 : || defined __amdfam10__)
56 : /* To swap the bytes in a word the i486 processors and up provide the
57 : `bswap' opcode. On i386 we have to use three instructions. */
58 : # define __bswap_32(x) \
59 : (__extension__ \
60 : ({ unsigned int __v, __x = (x); \
61 : if (__builtin_constant_p (__x)) \
62 : __v = __bswap_constant_32 (__x); \
63 : else \
64 : __asm__ ("bswap %0" : "=r" (__v) : "0" (__x)); \
65 : __v; }))
66 : # else
67 : # define __bswap_32(x) \
68 : (__extension__ \
69 : ({ unsigned int __v, __x = (x); \
70 : if (__builtin_constant_p (__x)) \
71 : __v = __bswap_constant_32 (__x); \
72 : else \
73 : __asm__ ("rorw $8, %w0;" \
74 : "rorl $16, %0;" \
75 : "rorw $8, %w0" \
76 : : "=r" (__v) \
77 : : "0" (__x) \
78 : : "cc"); \
79 : __v; }))
80 : # endif
81 : # else
82 : # define __bswap_32(x) \
83 : (__extension__ \
84 : ({ unsigned int __x = (x); __bswap_constant_32 (__x); }))
85 : # endif
86 : #else
87 : static __inline unsigned int
88 : __bswap_32 (unsigned int __bsx)
89 : {
90 : return __bswap_constant_32 (__bsx);
91 : }
92 : #endif
93 :
94 :
95 : #if __GNUC_PREREQ (2, 0)
96 : /* Swap bytes in 64 bit value. */
97 : # define __bswap_constant_64(x) \
98 : (__extension__ ((((x) & 0xff00000000000000ull) >> 56) \
99 : | (((x) & 0x00ff000000000000ull) >> 40) \
100 : | (((x) & 0x0000ff0000000000ull) >> 24) \
101 : | (((x) & 0x000000ff00000000ull) >> 8) \
102 : | (((x) & 0x00000000ff000000ull) << 8) \
103 : | (((x) & 0x0000000000ff0000ull) << 24) \
104 : | (((x) & 0x000000000000ff00ull) << 40) \
105 : | (((x) & 0x00000000000000ffull) << 56)))
106 :
107 : # if __GNUC_PREREQ (4, 3)
108 : static __inline __uint64_t
109 : __bswap_64 (__uint64_t __bsx)
110 : {
111 : return __builtin_bswap64 (__bsx);
112 : }
113 : # elif __WORDSIZE == 64
114 : # define __bswap_64(x) \
115 : (__extension__ \
116 : ({ __uint64_t __v, __x = (x); \
117 : if (__builtin_constant_p (__x)) \
118 : __v = __bswap_constant_64 (__x); \
119 : else \
120 : __asm__ ("bswap %q0" : "=r" (__v) : "0" (__x)); \
121 : __v; }))
122 : # else
123 : # define __bswap_64(x) \
124 : (__extension__ \
125 : ({ union { __extension__ __uint64_t __ll; \
126 : unsigned int __l[2]; } __w, __r; \
127 : if (__builtin_constant_p (x)) \
128 : __r.__ll = __bswap_constant_64 (x); \
129 : else \
130 : { \
131 : __w.__ll = (x); \
132 : __r.__l[0] = __bswap_32 (__w.__l[1]); \
133 : __r.__l[1] = __bswap_32 (__w.__l[0]); \
134 : } \
135 : __r.__ll; }))
136 : # endif
137 : #else
138 : # define __bswap_constant_64(x) \
139 : ((((x) & 0xff00000000000000ull) >> 56) \
140 : | (((x) & 0x00ff000000000000ull) >> 40) \
141 : | (((x) & 0x0000ff0000000000ull) >> 24) \
142 : | (((x) & 0x000000ff00000000ull) >> 8) \
143 : | (((x) & 0x00000000ff000000ull) << 8) \
144 : | (((x) & 0x0000000000ff0000ull) << 24) \
145 : | (((x) & 0x000000000000ff00ull) << 40) \
146 : | (((x) & 0x00000000000000ffull) << 56))
147 :
148 : static __inline __uint64_t
149 : __bswap_64 (__uint64_t __bsx)
150 : {
151 : return __bswap_constant_64 (__bsx);
152 : }
153 : #endif
154 :
155 : #endif /* _BITS_BYTESWAP_H */
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