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| Rev | Author | Line No. | Line |
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| 63 | pj | 1 | /* Macros to swap the order of bytes in integer values. |
| 2 | Copyright (C) 1997, 1998, 2000, 2002 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |||
| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |||
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |||
| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, write to the Free |
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| 17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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| 18 | 02111-1307 USA. */ |
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| 19 | |||
| 20 | #if !defined _BYTESWAP_H && !defined _NETINET_IN_H |
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| 21 | # error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead." |
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| 22 | #endif |
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| 23 | |||
| 24 | #ifndef _BITS_BYTESWAP_H |
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| 25 | #define _BITS_BYTESWAP_H 1 |
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| 26 | |||
| 27 | /* Swap bytes in 16 bit value. */ |
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| 28 | #define __bswap_constant_16(x) \ |
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| 29 | ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)) |
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| 30 | |||
| 31 | #if defined __GNUC__ && __GNUC__ >= 2 |
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| 32 | # define __bswap_16(x) \ |
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| 33 | (__extension__ \ |
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| 34 | ({ register unsigned short int __v; \ |
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| 35 | if (__builtin_constant_p (x)) \ |
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| 36 | __v = __bswap_constant_16 (x); \ |
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| 37 | else \ |
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| 38 | __asm__ __volatile__ ("rorw $8, %w0" \ |
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| 39 | : "=r" (__v) \ |
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| 40 | : "0" ((unsigned short int) (x)) \ |
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| 41 | : "cc"); \ |
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| 42 | __v; })) |
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| 43 | #else |
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| 44 | /* This is better than nothing. */ |
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| 45 | # define __bswap_16(x) __bswap_constant_16 (x) |
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| 46 | #endif |
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| 47 | |||
| 48 | |||
| 49 | /* Swap bytes in 32 bit value. */ |
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| 50 | #define __bswap_constant_32(x) \ |
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| 51 | ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \ |
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| 52 | (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24)) |
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| 53 | |||
| 54 | #if defined __GNUC__ && __GNUC__ >= 2 |
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| 55 | /* To swap the bytes in a word the i486 processors and up provide the |
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| 56 | `bswap' opcode. On i386 we have to use three instructions. */ |
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| 57 | # if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ |
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| 58 | # define __bswap_32(x) \ |
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| 59 | (__extension__ \ |
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| 60 | ({ register unsigned int __v; \ |
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| 61 | if (__builtin_constant_p (x)) \ |
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| 62 | __v = __bswap_constant_32 (x); \ |
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| 63 | else \ |
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| 64 | __asm__ __volatile__ ("rorw $8, %w0;" \ |
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| 65 | "rorl $16, %0;" \ |
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| 66 | "rorw $8, %w0" \ |
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| 67 | : "=r" (__v) \ |
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| 68 | : "0" ((unsigned int) (x)) \ |
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| 69 | : "cc"); \ |
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| 70 | __v; })) |
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| 71 | # else |
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| 72 | # define __bswap_32(x) \ |
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| 73 | (__extension__ \ |
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| 74 | ({ register unsigned int __v; \ |
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| 75 | if (__builtin_constant_p (x)) \ |
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| 76 | __v = __bswap_constant_32 (x); \ |
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| 77 | else \ |
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| 78 | __asm__ __volatile__ ("bswap %0" \ |
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| 79 | : "=r" (__v) \ |
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| 80 | : "0" ((unsigned int) (x))); \ |
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| 81 | __v; })) |
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| 82 | # endif |
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| 83 | #else |
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| 84 | # define __bswap_32(x) __bswap_constant_32 (x) |
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| 85 | #endif |
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| 86 | |||
| 87 | |||
| 88 | #if defined __GNUC__ && __GNUC__ >= 2 |
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| 89 | /* Swap bytes in 64 bit value. */ |
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| 90 | #define __bswap_constant_64(x) \ |
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| 91 | ((((x) & 0xff00000000000000ull) >> 56) \ |
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| 92 | | (((x) & 0x00ff000000000000ull) >> 40) \ |
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| 93 | | (((x) & 0x0000ff0000000000ull) >> 24) \ |
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| 94 | | (((x) & 0x000000ff00000000ull) >> 8) \ |
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| 95 | | (((x) & 0x00000000ff000000ull) << 8) \ |
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| 96 | | (((x) & 0x0000000000ff0000ull) << 24) \ |
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| 97 | | (((x) & 0x000000000000ff00ull) << 40) \ |
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| 98 | | (((x) & 0x00000000000000ffull) << 56)) |
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| 99 | |||
| 100 | # define __bswap_64(x) \ |
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| 101 | (__extension__ \ |
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| 102 | ({ union { __extension__ unsigned long long int __ll; \ |
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| 103 | unsigned long int __l[2]; } __w, __r; \ |
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| 104 | if (__builtin_constant_p (x)) \ |
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| 105 | __r.__ll = __bswap_constant_64 (x); \ |
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| 106 | else \ |
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| 107 | { \ |
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| 108 | __w.__ll = (x); \ |
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| 109 | __r.__l[0] = __bswap_32 (__w.__l[1]); \ |
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| 110 | __r.__l[1] = __bswap_32 (__w.__l[0]); \ |
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| 111 | } \ |
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| 112 | __r.__ll; })) |
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| 113 | #endif |
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| 114 | |||
| 115 | #endif /* _BITS_BYTESWAP_H */ |