byte_swap.h

基于组件方式开发操作系统的OSKIT源代码

/*	$NetBSD: byte_swap.h,v 1.2 2000/03/16 14:15:26 mycroft Exp $	*/

/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#ifndef _I386_BYTE_SWAP_H_
#define	_I386_BYTE_SWAP_H_

#if defined(_KERNEL) && !defined(_LKM)
#include "opt_cputype.h"
#endif

#if defined(_KERNEL) && !defined(_LKM) && !defined(I386_CPU)
#define	__byte_swap_long_variable(x) __extension__ \
({ register in_addr_t __x = (x); \
   __asm ("bswap %1" \
	: "=r" (__x) \
	: "0" (__x)); \
   __x; })
#else
#define	__byte_swap_long_variable(x) __extension__ \
({ register in_addr_t __x = (x); \
   __asm ("rorw $8, %w1\n\trorl $16, %1\n\trorw $8, %w1" \
	: "=r" (__x) \
	: "0" (__x)); \
   __x; })
#endif	/* _KERNEL && ... */

#define	__byte_swap_word_variable(x) __extension__ \
({ register in_port_t __x = (x); \
   __asm ("rorw $8, %w1" \
	: "=r" (__x) \
	: "0" (__x)); \
   __x; })

#ifdef __OPTIMIZE__

#define	__byte_swap_long_constant(x) \
	((((x) & 0xff000000) >> 24) | \
	 (((x) & 0x00ff0000) >>  8) | \
	 (((x) & 0x0000ff00) <<  8) | \
	 (((x) & 0x000000ff) << 24))
#define	__byte_swap_word_constant(x) \
	((((x) & 0xff00) >> 8) | \
	 (((x) & 0x00ff) << 8))
#define	__byte_swap_long(x) \
	(__builtin_constant_p((x)) ? \
	 __byte_swap_long_constant(x) : __byte_swap_long_variable(x))
#define	__byte_swap_word(x) \
	(__builtin_constant_p((x)) ? \
	 __byte_swap_word_constant(x) : __byte_swap_word_variable(x))

#else /* __OPTIMIZE__ */

#define	__byte_swap_long(x)	__byte_swap_long_variable(x)
#define	__byte_swap_word(x)	__byte_swap_word_variable(x)

#endif /* __OPTIMIZE__ */

#endif /* !_I386_BYTE_SWAP_H_ */