osfmk/i386/endian.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  *
  25  */
  26
  27 #ifndef _MACHINE_ENDIAN_H_
  28 #define _MACHINE_ENDIAN_H_
  29
  30 /*
  31  * Definitions for byte order,
  32  * according to byte significance from low address to high.
  33  */
  34 #define LITTLE_ENDIAN   1234    /* least-significant byte first (vax) */
  35 #define BIG_ENDIAN      4321    /* most-significant byte first (IBM, net) */
  36 #define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp) */
  37
  38 #define BYTE_ORDER      LITTLE_ENDIAN   /* byte order on i386 */
  39 #define ENDIAN          LITTLE
  40
  41 /*
  42  * Macros for network/external number representation conversion.
  43  */
  44
  45 unsigned short  ntohs(unsigned short), htons(unsigned short);
  46 unsigned long   ntohl(unsigned long), htonl(unsigned long);
  47
  48 /*
  49  * Use GNUC support to inline the byteswappers.
  50  */
  51
  52 extern __inline__
  53 unsigned short
  54 ntohs(unsigned short w_int)
  55 {
  56         register unsigned short w = w_int;
  57         __asm__ volatile("xchgb %h1,%b1" : "=q" (w) : "0" (w));
  58         return (w);     /* zero-extend for compat */
  59 }
  60
  61 #define htons   ntohs
  62
  63 extern __inline__
  64 unsigned long
  65 ntohl(register unsigned long value)
  66 {
  67         register unsigned long l = value;
  68         __asm__ volatile("bswap %0" : "=r" (l) : "0" (l));
  69         return l;
  70 }
  71
  72 #define htonl   ntohl
  73
  74 #define NTOHL(x)        (x) = ntohl((unsigned long)x)
  75 #define NTOHS(x)        (x) = ntohs((unsigned short)x)
  76 #define HTONL(x)        (x) = htonl((unsigned long)x)
  77 #define HTONS(x)        (x) = htons((unsigned short)x)
  78
  79 #endif