endian.h

C++ 编写的EROS RTOS

/*	$NetBSD: endian.h,v 1.16 1995/06/01 17:19:18 mycroft Exp $	*/

/*
 * Copyright (c) 1995 Charles M. Hannum.  All rights reserved.
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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
 */

#ifndef _I386_ENDIAN_H_
#define	_I386_ENDIAN_H_

/*
 * Define the order of 32-bit words in 64-bit words.
 */
#define _QUAD_HIGHWORD 1
#define _QUAD_LOWWORD 0


#ifndef _POSIX_SOURCE
/*
 * 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

unsigned long   htonl (unsigned long);
unsigned short  htons (unsigned short);
unsigned long   ntohl (unsigned long);
unsigned short  ntohs (unsigned short);


#ifdef __GNUC__

#if defined(_KERNEL) && !defined(I386_CPU)
#define	__byte_swap_long_variable(x) \
({ register unsigned long __x = (x); \
   __asm ("bswap %1" \
	: "=r" (__x) \
	: "0" (__x)); \
   __x; })
#else
#define	__byte_swap_long_variable(x) \
({ register unsigned long __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) \
({ register unsigned short __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__ */

#define	ntohl(x)	__byte_swap_long(x)
#define	ntohs(x)	__byte_swap_word(x)
#define	htonl(x)	__byte_swap_long(x)
#define	htons(x)	__byte_swap_word(x)

#endif	/* __GNUC__ */


/*
 * Macros for network/external number representation conversion.
 */
#define	NTOHL(x)	((x) = ntohl((unsigned long)(x)))
#define	NTOHS(x)	((x) = ntohs((unsigned short)(x)))
#define	HTONL(x)	((x) = htonl((unsigned long)(x)))
#define	HTONS(x)	((x) = htons((unsigned short)(x)))

#endif /* _POSIX_SOURCE */

#endif /* !_I386_ENDIAN_H_ */