sys/i386/include/endian.h

/*
 * 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.
 *
 *      from: @(#)endian.h      7.8 (Berkeley) 4/3/91
 *      $Id$
 */

/*
 * 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