1/* Macros to swap the order of bytes in integer values. 2 Copyright (C) 1997, 1998, 2000, 2002, 2003 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#include <bits/wordsize.h> 28 29/* Swap bytes in 16 bit value. */ 30#define __bswap_constant_16(x) \ 31 ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)) 32 33#if defined __GNUC__ && __GNUC__ >= 2 34# define __bswap_16(x) \ 35 (__extension__ \ 36 ({ register unsigned short int __v, __x = (x); \ 37 if (__builtin_constant_p (__x)) \ 38 __v = __bswap_constant_16 (__x); \ 39 else \ 40 __asm__ ("rorw $8, %w0" \ 41 : "=r" (__v) \ 42 : "0" (__x) \ 43 : "cc"); \ 44 __v; })) 45#else 46/* This is better than nothing. */ 47# define __bswap_16(x) \ 48 (__extension__ \ 49 ({ register unsigned short int __x = (x); __bswap_constant_16 (__x); })) 50#endif 51 52 53/* Swap bytes in 32 bit value. */ 54#define __bswap_constant_32(x) \ 55 ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \ 56 (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24)) 57 58#if defined __GNUC__ && __GNUC__ >= 2 59# if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__ \ 60 || defined __pentiumpro__ || defined __pentium4__ \ 61 || defined __k8__ || defined __athlon__ \ 62 || defined __k6__) 63/* To swap the bytes in a word the i486 processors and up provide the 64 `bswap' opcode. On i386 we have to use three instructions. */ 65# define __bswap_32(x) \ 66 (__extension__ \ 67 ({ register unsigned int __v, __x = (x); \ 68 if (__builtin_constant_p (__x)) \ 69 __v = __bswap_constant_32 (__x); \ 70 else \ 71 __asm__ ("bswap %0" : "=r" (__v) : "0" (__x)); \ 72 __v; })) 73# else 74# define __bswap_32(x) \ 75 (__extension__ \ 76 ({ register unsigned int __v, __x = (x); \ 77 if (__builtin_constant_p (__x)) \ 78 __v = __bswap_constant_32 (__x); \ 79 else \ 80 __asm__ ("rorw $8, %w0;" \ 81 "rorl $16, %0;" \ 82 "rorw $8, %w0" \ 83 : "=r" (__v) \ 84 : "0" (__x) \ 85 : "cc"); \ 86 __v; })) 87# endif 88#else 89# define __bswap_32(x) \ 90 (__extension__ \ 91 ({ register unsigned int __x = (x); __bswap_constant_32 (__x); })) 92#endif 93 94 95#if defined __GNUC__ && __GNUC__ >= 2 96/* Swap bytes in 64 bit value. */ 97# define __bswap_constant_64(x) \ 98 ((((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 __WORDSIZE == 64 108# define __bswap_64(x) \ 109 (__extension__ \ 110 ({ register unsigned long __v, __x = (x); \ 111 if (__builtin_constant_p (__x)) \ 112 __v = __bswap_constant_64 (__x); \ 113 else \ 114 __asm__ ("bswap %q0" : "=r" (__v) : "0" (__x)); \ 115 __v; })) 116# else 117# define __bswap_64(x) \ 118 (__extension__ \ 119 ({ union { __extension__ unsigned long long int __ll; \ 120 unsigned int __l[2]; } __w, __r; \ 121 if (__builtin_constant_p (x)) \ 122 __r.__ll = __bswap_constant_64 (x); \ 123 else \ 124 { \ 125 __w.__ll = (x); \ 126 __r.__l[0] = __bswap_32 (__w.__l[1]); \ 127 __r.__l[1] = __bswap_32 (__w.__l[0]); \ 128 } \ 129 __r.__ll; })) 130# endif 131#endif 132 133#endif /* _BITS_BYTESWAP_H */ 134