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156 lines
5.5 KiB
C
156 lines
5.5 KiB
C
/* Macros to swap the order of bytes in integer values.
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Copyright (C) 1997-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
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# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
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#endif
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#ifndef _BITS_BYTESWAP_H
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#define _BITS_BYTESWAP_H 1
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#include <features.h>
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#include <bits/types.h>
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#include <bits/wordsize.h>
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/* Swap bytes in 16 bit value. */
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#define __bswap_constant_16(x) \
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((unsigned short int) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
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/* Get __bswap_16. */
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#include <bits/byteswap-16.h>
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/* Swap bytes in 32 bit value. */
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#define __bswap_constant_32(x) \
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((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
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(((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
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#ifdef __GNUC__
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# if __GNUC_PREREQ (4, 3)
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static __inline unsigned int
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__bswap_32 (unsigned int __bsx)
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{
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return __builtin_bswap32 (__bsx);
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}
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# elif __GNUC__ >= 2
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# if __WORDSIZE == 64 || (defined __i486__ || defined __pentium__ \
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|| defined __pentiumpro__ || defined __pentium4__ \
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|| defined __k8__ || defined __athlon__ \
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|| defined __k6__ || defined __nocona__ \
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|| defined __core2__ || defined __geode__ \
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|| defined __amdfam10__)
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/* To swap the bytes in a word the i486 processors and up provide the
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`bswap' opcode. On i386 we have to use three instructions. */
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# define __bswap_32(x) \
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(__extension__ \
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({ unsigned int __v, __x = (x); \
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if (__builtin_constant_p (__x)) \
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__v = __bswap_constant_32 (__x); \
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else \
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__asm__ ("bswap %0" : "=r" (__v) : "0" (__x)); \
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__v; }))
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# else
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# define __bswap_32(x) \
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(__extension__ \
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({ unsigned int __v, __x = (x); \
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if (__builtin_constant_p (__x)) \
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__v = __bswap_constant_32 (__x); \
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else \
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__asm__ ("rorw $8, %w0;" \
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"rorl $16, %0;" \
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"rorw $8, %w0" \
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: "=r" (__v) \
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: "0" (__x) \
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: "cc"); \
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__v; }))
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# endif
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# else
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# define __bswap_32(x) \
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(__extension__ \
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({ unsigned int __x = (x); __bswap_constant_32 (__x); }))
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# endif
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#else
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static __inline unsigned int
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__bswap_32 (unsigned int __bsx)
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{
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return __bswap_constant_32 (__bsx);
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}
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#endif
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#if __GNUC_PREREQ (2, 0)
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/* Swap bytes in 64 bit value. */
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# define __bswap_constant_64(x) \
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(__extension__ ((((x) & 0xff00000000000000ull) >> 56) \
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| (((x) & 0x00ff000000000000ull) >> 40) \
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| (((x) & 0x0000ff0000000000ull) >> 24) \
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| (((x) & 0x000000ff00000000ull) >> 8) \
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| (((x) & 0x00000000ff000000ull) << 8) \
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| (((x) & 0x0000000000ff0000ull) << 24) \
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| (((x) & 0x000000000000ff00ull) << 40) \
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| (((x) & 0x00000000000000ffull) << 56)))
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# if __GNUC_PREREQ (4, 3)
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static __inline __uint64_t
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__bswap_64 (__uint64_t __bsx)
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{
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return __builtin_bswap64 (__bsx);
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}
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# elif __WORDSIZE == 64
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# define __bswap_64(x) \
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(__extension__ \
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({ __uint64_t __v, __x = (x); \
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if (__builtin_constant_p (__x)) \
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__v = __bswap_constant_64 (__x); \
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else \
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__asm__ ("bswap %q0" : "=r" (__v) : "0" (__x)); \
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__v; }))
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# else
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# define __bswap_64(x) \
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(__extension__ \
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({ union { __extension__ __uint64_t __ll; \
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unsigned int __l[2]; } __w, __r; \
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if (__builtin_constant_p (x)) \
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__r.__ll = __bswap_constant_64 (x); \
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else \
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{ \
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__w.__ll = (x); \
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__r.__l[0] = __bswap_32 (__w.__l[1]); \
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__r.__l[1] = __bswap_32 (__w.__l[0]); \
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} \
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__r.__ll; }))
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# endif
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#else
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# define __bswap_constant_64(x) \
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((((x) & 0xff00000000000000ull) >> 56) \
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| (((x) & 0x00ff000000000000ull) >> 40) \
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| (((x) & 0x0000ff0000000000ull) >> 24) \
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| (((x) & 0x000000ff00000000ull) >> 8) \
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| (((x) & 0x00000000ff000000ull) << 8) \
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| (((x) & 0x0000000000ff0000ull) << 24) \
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| (((x) & 0x000000000000ff00ull) << 40) \
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| (((x) & 0x00000000000000ffull) << 56))
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static __inline __uint64_t
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__bswap_64 (__uint64_t __bsx)
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{
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return __bswap_constant_64 (__bsx);
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}
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#endif
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#endif /* _BITS_BYTESWAP_H */
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