mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-26 23:10:06 +00:00
2f9a1be867
* string/endian.h: Add macros for fixed-size endian conversion. * bits/byteswap.h: Allow inclusion from <endian.h>. * sysdeps/i386/bits/byteswap.h: Likewise. * sysdeps/ia64/bits/byteswap.h: Likewise. * sysdeps/s390/bits/byteswap.h: Likewise. * sysdeps/x86_64/bits/byteswap.h: Likewise. * string/Makefile (tests): Add tst-endian. * string/tst-endian.c: New file.
137 lines
4.7 KiB
C
137 lines
4.7 KiB
C
/* Macros to swap the order of bytes in integer values.
|
|
Copyright (C) 1997, 1998, 2000, 2002, 2003, 2006, 2007, 2008
|
|
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 Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; 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 && !defined _ENDIAN_H
|
|
# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
|
|
#endif
|
|
|
|
#ifndef _BITS_BYTESWAP_H
|
|
#define _BITS_BYTESWAP_H 1
|
|
|
|
/* Swap bytes in 16 bit value. */
|
|
#define __bswap_constant_16(x) \
|
|
((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
|
|
|
|
#ifdef __GNUC__
|
|
# if __GNUC__ >= 2
|
|
# define __bswap_16(x) \
|
|
(__extension__ \
|
|
({ register unsigned short int __v, __x = (x); \
|
|
if (__builtin_constant_p (__x)) \
|
|
__v = __bswap_constant_16 (__x); \
|
|
else \
|
|
__asm__ ("rorw $8, %w0" \
|
|
: "=r" (__v) \
|
|
: "0" (__x) \
|
|
: "cc"); \
|
|
__v; }))
|
|
# else
|
|
/* This is better than nothing. */
|
|
# define __bswap_16(x) \
|
|
(__extension__ \
|
|
({ register unsigned short int __x = (x); __bswap_constant_16 (__x); }))
|
|
# endif
|
|
#else
|
|
static __inline unsigned short int
|
|
__bswap_16 (unsigned short int __bsx)
|
|
{
|
|
return __bswap_constant_16 (__bsx);
|
|
}
|
|
#endif
|
|
|
|
/* Swap bytes in 32 bit value. */
|
|
#define __bswap_constant_32(x) \
|
|
((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
|
|
(((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
|
|
|
|
#ifdef __GNUC__
|
|
# if __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. */
|
|
# if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ \
|
|
&& !defined __pentium4__ && !defined __k8__ && !defined __athlon__ \
|
|
&& !defined __k6__ && !defined __nocona__ && !defined __core2__ \
|
|
&& !defined __geode__ && !defined __amdfam10__
|
|
# define __bswap_32(x) \
|
|
(__extension__ \
|
|
({ register unsigned int __v, __x = (x); \
|
|
if (__builtin_constant_p (__x)) \
|
|
__v = __bswap_constant_32 (__x); \
|
|
else \
|
|
__asm__ ("rorw $8, %w0;" \
|
|
"rorl $16, %0;" \
|
|
"rorw $8, %w0" \
|
|
: "=r" (__v) \
|
|
: "0" (__x) \
|
|
: "cc"); \
|
|
__v; }))
|
|
# else
|
|
# define __bswap_32(x) \
|
|
(__extension__ \
|
|
({ register unsigned int __v, __x = (x); \
|
|
if (__builtin_constant_p (__x)) \
|
|
__v = __bswap_constant_32 (__x); \
|
|
else \
|
|
__asm__ ("bswap %0" : "=r" (__v) : "0" (__x)); \
|
|
__v; }))
|
|
# endif
|
|
# else
|
|
# define __bswap_32(x) \
|
|
(__extension__ \
|
|
({ register unsigned int __x = (x); __bswap_constant_32 (__x); }))
|
|
# endif
|
|
#else
|
|
static __inline unsigned int
|
|
__bswap_32 (unsigned int __bsx)
|
|
{
|
|
return __bswap_constant_32 (__bsx);
|
|
}
|
|
#endif
|
|
|
|
|
|
#if defined __GNUC__ && __GNUC__ >= 2
|
|
/* Swap bytes in 64 bit value. */
|
|
#define __bswap_constant_64(x) \
|
|
((((x) & 0xff00000000000000ull) >> 56) \
|
|
| (((x) & 0x00ff000000000000ull) >> 40) \
|
|
| (((x) & 0x0000ff0000000000ull) >> 24) \
|
|
| (((x) & 0x000000ff00000000ull) >> 8) \
|
|
| (((x) & 0x00000000ff000000ull) << 8) \
|
|
| (((x) & 0x0000000000ff0000ull) << 24) \
|
|
| (((x) & 0x000000000000ff00ull) << 40) \
|
|
| (((x) & 0x00000000000000ffull) << 56))
|
|
|
|
# define __bswap_64(x) \
|
|
(__extension__ \
|
|
({ union { __extension__ unsigned long long int __ll; \
|
|
unsigned long int __l[2]; } __w, __r; \
|
|
if (__builtin_constant_p (x)) \
|
|
__r.__ll = __bswap_constant_64 (x); \
|
|
else \
|
|
{ \
|
|
__w.__ll = (x); \
|
|
__r.__l[0] = __bswap_32 (__w.__l[1]); \
|
|
__r.__l[1] = __bswap_32 (__w.__l[0]); \
|
|
} \
|
|
__r.__ll; }))
|
|
#endif
|
|
|
|
#endif /* _BITS_BYTESWAP_H */
|