osfmk/i386/endian.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  *
  28  */
  29
  30 #ifndef _MACHINE_ENDIAN_H_
  31 #define _MACHINE_ENDIAN_H_
  32
  33 /*
  34  * Definitions for byte order,
  35  * according to byte significance from low address to high.
  36  */
  37 #define LITTLE_ENDIAN   1234    /* least-significant byte first (vax) */
  38 #define BIG_ENDIAN      4321    /* most-significant byte first (IBM, net) */
  39 #define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp) */
  40
  41 #define BYTE_ORDER      LITTLE_ENDIAN   /* byte order on i386 */
  42 #define ENDIAN          LITTLE
  43
  44 /*
  45  * Macros for network/external number representation conversion.
  46  */
  47
  48 unsigned short  ntohs(unsigned short), htons(unsigned short);
  49 unsigned long   ntohl(unsigned long), htonl(unsigned long);
  50
  51 /*
  52  * Use GNUC support to inline the byteswappers.
  53  */
  54
  55 extern __inline__
  56 unsigned short
  57 ntohs(unsigned short w_int)
  58 {
  59         register unsigned short w = w_int;
  60         __asm__ volatile("xchgb %h1,%b1" : "=q" (w) : "0" (w));
  61         return (w);     /* zero-extend for compat */
  62 }
  63
  64 #define htons   ntohs
  65
  66 extern __inline__
  67 unsigned long
  68 ntohl(register unsigned long value)
  69 {
  70         register unsigned long l = value;
  71         __asm__ volatile("bswap %0" : "=r" (l) : "0" (l));
  72         return l;
  73 }
  74
  75 #define htonl   ntohl
  76
  77 #define NTOHL(x)        (x) = ntohl((unsigned long)x)
  78 #define NTOHS(x)        (x) = ntohs((unsigned short)x)
  79 #define HTONL(x)        (x) = htonl((unsigned long)x)
  80 #define HTONS(x)        (x) = htons((unsigned short)x)
  81
  82 #endif