1 /* Macros to swap the order of bytes in integer values. 2 Copyright (C) 1997-2016 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 29 /* Swap bytes in 16 bit value. */ 30 #define __bswap_constant_16(x) \ 31 ((unsigned short int)((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))) 32 33 /* Get __bswap_16. */ 34 #include <bits/byteswap-16.h> 35 36 /* Swap bytes in 32 bit value. */ 37 #define __bswap_constant_32(x) \ 38 ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) | \ 39 (((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24)) 40 41 #ifdef __GNUC__ 42 # if __GNUC_PREREQ (4, 3) 43 static __inline unsigned int __bswap_32(unsigned int __bsx)44__bswap_32 (unsigned int __bsx) 45 { 46 return __builtin_bswap32 (__bsx); 47 } 48 # else 49 # define __bswap_32(x) \ 50 (__extension__ \ 51 ({ unsigned int __bsx = (x); __bswap_constant_32 (__bsx); })) 52 # endif 53 #else 54 static __inline unsigned int __bswap_32(unsigned int __bsx)55__bswap_32 (unsigned int __bsx) 56 { 57 return __bswap_constant_32 (__bsx); 58 } 59 #endif 60 61 /* Swap bytes in 64 bit value. */ 62 #if __GNUC_PREREQ (2, 0) 63 # define __bswap_constant_64(x) \ 64 (__extension__ ((((x) & 0xff00000000000000ull) >> 56) \ 65 | (((x) & 0x00ff000000000000ull) >> 40) \ 66 | (((x) & 0x0000ff0000000000ull) >> 24) \ 67 | (((x) & 0x000000ff00000000ull) >> 8) \ 68 | (((x) & 0x00000000ff000000ull) << 8) \ 69 | (((x) & 0x0000000000ff0000ull) << 24) \ 70 | (((x) & 0x000000000000ff00ull) << 40) \ 71 | (((x) & 0x00000000000000ffull) << 56))) 72 73 # if __GNUC_PREREQ (4, 3) 74 static __inline __uint64_t __bswap_64(__uint64_t __bsx)75__bswap_64 (__uint64_t __bsx) 76 { 77 return __builtin_bswap64 (__bsx); 78 } 79 # else 80 # define __bswap_64(x) \ 81 (__extension__ \ 82 ({ union { __extension__ __uint64_t __ll; \ 83 unsigned int __l[2]; } __w, __r; \ 84 if (__builtin_constant_p (x)) \ 85 __r.__ll = __bswap_constant_64 (x); \ 86 else \ 87 { \ 88 __w.__ll = (x); \ 89 __r.__l[0] = __bswap_32 (__w.__l[1]); \ 90 __r.__l[1] = __bswap_32 (__w.__l[0]); \ 91 } \ 92 __r.__ll; })) 93 # endif 94 #else 95 # define __bswap_constant_64(x) \ 96 ((((x) & 0xff00000000000000ull) >> 56) \ 97 | (((x) & 0x00ff000000000000ull) >> 40) \ 98 | (((x) & 0x0000ff0000000000ull) >> 24) \ 99 | (((x) & 0x000000ff00000000ull) >> 8) \ 100 | (((x) & 0x00000000ff000000ull) << 8) \ 101 | (((x) & 0x0000000000ff0000ull) << 24) \ 102 | (((x) & 0x000000000000ff00ull) << 40) \ 103 | (((x) & 0x00000000000000ffull) << 56)) 104 105 static __inline __uint64_t __bswap_64(__uint64_t __bsx)106__bswap_64 (__uint64_t __bsx) 107 { 108 return __bswap_constant_64 (__bsx); 109 } 110 #endif 111 112 #endif /* _BITS_BYTESWAP_H */ 113