1 | /* Macros to swap the order of bytes in integer values. |
2 | Copyright (C) 1997-2018 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 | __bswap_32 (unsigned int __bsx) |
46 | { |
47 | 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 */ |
156 | |