osfmk/i386/endian.h

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  *
  31  */
  32
  33 #ifndef _MACHINE_ENDIAN_H_
  34 #define _MACHINE_ENDIAN_H_
  35
  36 /*
  37  * Definitions for byte order,
  38  * according to byte significance from low address to high.
  39  */
  40 #define LITTLE_ENDIAN   1234    /* least-significant byte first (vax) */
  41 #define BIG_ENDIAN      4321    /* most-significant byte first (IBM, net) */
  42 #define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp) */
  43
  44 #define BYTE_ORDER      LITTLE_ENDIAN   /* byte order on i386 */
  45 #define ENDIAN          LITTLE
  46
  47 /*
  48  * Macros for network/external number representation conversion.
  49  * Use GNUC support to inline the byteswappers.
  50  */
  51
  52 #if !defined(ntohs)
  53 unsigned short  ntohs(unsigned short);
  54 extern __inline__
  55 unsigned short
  56 ntohs(unsigned short w_int)
  57 {
  58         register unsigned short w = w_int;
  59         __asm__ volatile("xchgb %h1,%b1" : "=q" (w) : "0" (w));
  60         return (w);     /* zero-extend for compat */
  61 }
  62 #endif
  63
  64 #if !defined(htons)
  65 unsigned short  htons(unsigned short);
  66 #define htons   ntohs
  67 #endif
  68
  69 #if !defined(ntohl)
  70 unsigned long   ntohl(unsigned long);
  71 extern __inline__
  72 unsigned long
  73 ntohl(register unsigned long value)
  74 {
  75         register unsigned long l = value;
  76         __asm__ volatile("bswap %0" : "=r" (l) : "0" (l));
  77         return l;
  78 }
  79 #endif
  80
  81 #if !defined(htonl)
  82 unsigned long   htonl(unsigned long);
  83 #define htonl   ntohl
  84 #endif
  85
  86 #define NTOHL(x)        (x) = ntohl((unsigned long)x)
  87 #define NTOHS(x)        (x) = ntohs((unsigned short)x)
  88 #define HTONL(x)        (x) = htonl((unsigned long)x)
  89 #define HTONS(x)        (x) = htons((unsigned short)x)
  90
  91 #endif