freebsd-dev/sys/x86/include/endian.h
Dimitry Andric 4715a95fb4 Revert sys/x86/include/endian.h to what it was before r233419, as that
revision has two problems:
- It can produce worse code with both clang and gcc.
- It doesn't fix the actual issue introduced in r232721, which will be
  fixed in the next commit.

Submitted by:	bde, tijl and jh
Pointy hat to:	dim
2012-03-29 23:30:17 +00:00

132 lines
4.0 KiB
C

/*-
* Copyright (c) 1987, 1991 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)endian.h 7.8 (Berkeley) 4/3/91
* $FreeBSD$
*/
#ifndef _MACHINE_ENDIAN_H_
#define _MACHINE_ENDIAN_H_
#include <sys/cdefs.h>
#include <sys/_types.h>
/*
* Define the order of 32-bit words in 64-bit words.
*/
#define _QUAD_HIGHWORD 1
#define _QUAD_LOWWORD 0
/*
* Definitions for byte order, according to byte significance from low
* address to high.
*/
#define _LITTLE_ENDIAN 1234 /* LSB first: i386, vax */
#define _BIG_ENDIAN 4321 /* MSB first: 68000, ibm, net */
#define _PDP_ENDIAN 3412 /* LSB first in word, MSW first in long */
#define _BYTE_ORDER _LITTLE_ENDIAN
/*
* Deprecated variants that don't have enough underscores to be useful in more
* strict namespaces.
*/
#if __BSD_VISIBLE
#define LITTLE_ENDIAN _LITTLE_ENDIAN
#define BIG_ENDIAN _BIG_ENDIAN
#define PDP_ENDIAN _PDP_ENDIAN
#define BYTE_ORDER _BYTE_ORDER
#endif
#define __bswap16_gen(x) (__uint16_t)((x) << 8 | (x) >> 8)
#define __bswap32_gen(x) \
(((__uint32_t)__bswap16(x) << 16) | __bswap16((x) >> 16))
#define __bswap64_gen(x) \
(((__uint64_t)__bswap32(x) << 32) | __bswap32((x) >> 32))
#ifdef __GNUCLIKE_BUILTIN_CONSTANT_P
#define __bswap16(x) \
((__uint16_t)(__builtin_constant_p(x) ? \
__bswap16_gen((__uint16_t)(x)) : __bswap16_var(x)))
#define __bswap32(x) \
(__builtin_constant_p(x) ? \
__bswap32_gen((__uint32_t)(x)) : __bswap32_var(x))
#define __bswap64(x) \
(__builtin_constant_p(x) ? \
__bswap64_gen((__uint64_t)(x)) : __bswap64_var(x))
#else
/* XXX these are broken for use in static initializers. */
#define __bswap16(x) __bswap16_var(x)
#define __bswap32(x) __bswap32_var(x)
#define __bswap64(x) __bswap64_var(x)
#endif
/* These are defined as functions to avoid multiple evaluation of x. */
static __inline __uint16_t
__bswap16_var(__uint16_t _x)
{
return (__bswap16_gen(_x));
}
static __inline __uint32_t
__bswap32_var(__uint32_t _x)
{
#ifdef __GNUCLIKE_ASM
__asm("bswap %0" : "+r" (_x));
return (_x);
#else
return (__bswap32_gen(_x));
#endif
}
static __inline __uint64_t
__bswap64_var(__uint64_t _x)
{
#if defined(__amd64__) && defined(__GNUCLIKE_ASM)
__asm("bswap %0" : "+r" (_x));
return (_x);
#else
/*
* It is important for the optimizations that the following is not
* really generic, but expands to 2 __bswap32_var()'s.
*/
return (__bswap64_gen(_x));
#endif
}
#define __htonl(x) __bswap32(x)
#define __htons(x) __bswap16(x)
#define __ntohl(x) __bswap32(x)
#define __ntohs(x) __bswap16(x)
#endif /* !_MACHINE_ENDIAN_H_ */