freebsd-src/sys/i386/include/endian.h
1993-06-12 14:58:17 +00:00

118 lines
3.8 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.
* 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
*
* PATCHES MAGIC LEVEL PATCH THAT GOT US HERE
* -------------------- ----- ----------------------
* CURRENT PATCH LEVEL: 1 00093
* -------------------- ----- ----------------------
*
* 27 Feb 93 Charles Hannum Better byte-swapping macros for
* i386/i486.
*/
/*
* 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
#ifndef KERNEL
#include <sys/cdefs.h>
#endif
#define __word_swap_long(x) \
({ register u_long X = (x); \
asm ("rorl $16, %1" \
: "=r" (X) \
: "0" (X)); \
X; })
#if __GNUC__ >= 2
#define __byte_swap_long(x) \
({ register u_long X = (x); \
asm ("xchgb %h1, %b1\n\trorl $16, %1\n\txchgb %h1, %b1" \
: "=q" (X) \
: "0" (X)); \
X; })
#define __byte_swap_word(x) \
({ register u_short X = (x); \
asm ("xchgb %h1, %b1" \
: "=q" (X) \
: "0" (X)); \
X; })
#else /* __GNUC__ >= 2 */
#define __byte_swap_long(x) \
({ register u_long X = (x); \
asm ("rorw $8, %w1\n\trorl $16, %1\n\trorw $8, %w1" \
: "=r" (X) \
: "0" (X)); \
X; })
#define __byte_swap_word(x) \
({ register u_short X = (x); \
asm ("rorw $8, %w1" \
: "=r" (X) \
: "0" (X)); \
X; })
#endif /* __GNUC__ >= 2 */
/*
* Macros for network/external number representation conversion.
*/
#if BYTE_ORDER == BIG_ENDIAN && !defined(lint)
#define ntohl(x) (x)
#define ntohs(x) (x)
#define htonl(x) (x)
#define htons(x) (x)
#define NTOHL(x) (x)
#define NTOHS(x) (x)
#define HTONL(x) (x)
#define HTONS(x) (x)
#else
#define ntohl __byte_swap_long
#define ntohs __byte_swap_word
#define htonl __byte_swap_long
#define htons __byte_swap_word
#define NTOHL(x) (x) = ntohl((u_long)x)
#define NTOHS(x) (x) = ntohs((u_short)x)
#define HTONL(x) (x) = htonl((u_long)x)
#define HTONS(x) (x) = htons((u_short)x)
#endif