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/* Macros to swap the order of bytes in integer values.
Copyright (C) 1997, 1998, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#if !defined _BYTESWAP_H && !defined _NETINET_IN_H
# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
#endif
/* Swap bytes in 16 bit value. */
#define __bswap_constant_16(x) \
((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
#if defined __GNUC__ && __GNUC__ >= 2
# define __bswap_16(x) \
(__extension__ \
({ register unsigned short int __v; \
if (__builtin_constant_p (x)) \
__v = __bswap_constant_16 (x); \
else \
__asm__ __volatile__ ("shl %0 = %1, 48 ;;" \
"mux1 %0 = %2, @rev ;;" \
: "=r" (__v) \
: "r" ((unsigned short int) (x)), "0" (__v));\
__v; }))
#else
/* This is better than nothing. */
# define __bswap_16(x) __bswap_constant_16 (x)
#endif
/* Swap bytes in 32 bit value. */
#define __bswap_constant_32(x) \
((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
(((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
#if defined __GNUC__ && __GNUC__ >= 2
/* To swap the bytes in a word the i486 processors and up provide the
`bswap' opcode. On i386 we have to use three instructions. */
# define __bswap_32(x) \
(__extension__ \
({ register unsigned int __v; \
if (__builtin_constant_p (x)) \
__v = __bswap_constant_32 (x); \
else \
__asm__ __volatile__ ("shl %0 = %1, 32 ;;" \
"mux1 %0 = %2, @rev ;;" \
: "=r" (__v) \
: "r" ((unsigned int) (x)), "0" (__v)); \
__v; }))
#else
# define __bswap_32(x) __bswap_constant_32 (x)
#endif
/* Swap bytes in 64 bit value. */
#define __bswap_constant_64(x) \
((((x) & 0xff00000000000000ul) >> 56) \
| (((x) & 0x00ff000000000000ul) >> 40) \
| (((x) & 0x0000ff0000000000ul) >> 24) \
| (((x) & 0x000000ff00000000ul) >> 8) \
| (((x) & 0x00000000ff000000ul) << 8) \
| (((x) & 0x0000000000ff0000ul) << 24) \
| (((x) & 0x000000000000ff00ul) << 40) \
| (((x) & 0x00000000000000fful) << 56))
#if defined __GNUC__ && __GNUC__ >= 2
# define __bswap_64(x) \
(__extension__ \
({ register unsigned long int __v; \
if (__builtin_constant_p (x)) \
__v = __bswap_constant_64 (x); \
else \
__asm__ __volatile__ ("mux1 %0 = %1, @rev ;;" \
: "=r" (__v) \
: "r" ((unsigned long int) (x))); \
__v; }))
#else
# define __bswap_64(x) __bswap_constant_64 (x)
#endif
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