Rev 63 | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
63 | pj | 1 | /* Macros to swap the order of bytes in integer values. |
2 | Copyright (C) 1997, 1998, 2000, 2002 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, write to the Free |
||
17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
||
18 | 02111-1307 USA. */ |
||
19 | |||
20 | #if !defined _BYTESWAP_H && !defined _NETINET_IN_H |
||
21 | # error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead." |
||
22 | #endif |
||
23 | |||
24 | #ifndef _BITS_BYTESWAP_H |
||
25 | #define _BITS_BYTESWAP_H 1 |
||
26 | |||
27 | /* Swap bytes in 16 bit value. */ |
||
28 | #define __bswap_constant_16(x) \ |
||
29 | ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)) |
||
30 | |||
31 | #if defined __GNUC__ && __GNUC__ >= 2 |
||
32 | # define __bswap_16(x) \ |
||
33 | (__extension__ \ |
||
34 | ({ register unsigned short int __v; \ |
||
35 | if (__builtin_constant_p (x)) \ |
||
36 | __v = __bswap_constant_16 (x); \ |
||
37 | else \ |
||
38 | __asm__ __volatile__ ("rorw $8, %w0" \ |
||
39 | : "=r" (__v) \ |
||
40 | : "0" ((unsigned short int) (x)) \ |
||
41 | : "cc"); \ |
||
42 | __v; })) |
||
43 | #else |
||
44 | /* This is better than nothing. */ |
||
45 | # define __bswap_16(x) __bswap_constant_16 (x) |
||
46 | #endif |
||
47 | |||
48 | |||
49 | /* Swap bytes in 32 bit value. */ |
||
50 | #define __bswap_constant_32(x) \ |
||
51 | ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \ |
||
52 | (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24)) |
||
53 | |||
54 | #if defined __GNUC__ && __GNUC__ >= 2 |
||
55 | /* To swap the bytes in a word the i486 processors and up provide the |
||
56 | `bswap' opcode. On i386 we have to use three instructions. */ |
||
57 | # if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ |
||
58 | # define __bswap_32(x) \ |
||
59 | (__extension__ \ |
||
60 | ({ register unsigned int __v; \ |
||
61 | if (__builtin_constant_p (x)) \ |
||
62 | __v = __bswap_constant_32 (x); \ |
||
63 | else \ |
||
64 | __asm__ __volatile__ ("rorw $8, %w0;" \ |
||
65 | "rorl $16, %0;" \ |
||
66 | "rorw $8, %w0" \ |
||
67 | : "=r" (__v) \ |
||
68 | : "0" ((unsigned int) (x)) \ |
||
69 | : "cc"); \ |
||
70 | __v; })) |
||
71 | # else |
||
72 | # define __bswap_32(x) \ |
||
73 | (__extension__ \ |
||
74 | ({ register unsigned int __v; \ |
||
75 | if (__builtin_constant_p (x)) \ |
||
76 | __v = __bswap_constant_32 (x); \ |
||
77 | else \ |
||
78 | __asm__ __volatile__ ("bswap %0" \ |
||
79 | : "=r" (__v) \ |
||
80 | : "0" ((unsigned int) (x))); \ |
||
81 | __v; })) |
||
82 | # endif |
||
83 | #else |
||
84 | # define __bswap_32(x) __bswap_constant_32 (x) |
||
85 | #endif |
||
86 | |||
87 | |||
88 | #if defined __GNUC__ && __GNUC__ >= 2 |
||
89 | /* Swap bytes in 64 bit value. */ |
||
90 | #define __bswap_constant_64(x) \ |
||
91 | ((((x) & 0xff00000000000000ull) >> 56) \ |
||
92 | | (((x) & 0x00ff000000000000ull) >> 40) \ |
||
93 | | (((x) & 0x0000ff0000000000ull) >> 24) \ |
||
94 | | (((x) & 0x000000ff00000000ull) >> 8) \ |
||
95 | | (((x) & 0x00000000ff000000ull) << 8) \ |
||
96 | | (((x) & 0x0000000000ff0000ull) << 24) \ |
||
97 | | (((x) & 0x000000000000ff00ull) << 40) \ |
||
98 | | (((x) & 0x00000000000000ffull) << 56)) |
||
99 | |||
100 | # define __bswap_64(x) \ |
||
101 | (__extension__ \ |
||
102 | ({ union { __extension__ unsigned long long int __ll; \ |
||
103 | unsigned long int __l[2]; } __w, __r; \ |
||
104 | if (__builtin_constant_p (x)) \ |
||
105 | __r.__ll = __bswap_constant_64 (x); \ |
||
106 | else \ |
||
107 | { \ |
||
108 | __w.__ll = (x); \ |
||
109 | __r.__l[0] = __bswap_32 (__w.__l[1]); \ |
||
110 | __r.__l[1] = __bswap_32 (__w.__l[0]); \ |
||
111 | } \ |
||
112 | __r.__ll; })) |
||
113 | #endif |
||
114 | |||
115 | #endif /* _BITS_BYTESWAP_H */ |