osfmk/ppc/endian.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * @OSF_COPYRIGHT@
  25  *
  26  */
  27
  28 #ifndef _MACHINE_ENDIAN_H_
  29 #define _MACHINE_ENDIAN_H_
  30
  31 /*
  32  * Definitions for byte order,
  33  * according to byte significance from low address to high.
  34  */
  35 #define LITTLE_ENDIAN   1234    /* least-significant byte first (vax) */
  36 #define BIG_ENDIAN      4321    /* most-significant byte first (IBM, net) */
  37 #define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp) */
  38
  39 #ifdef __BIG_ENDIAN__                   /* Predefined by compiler */
  40 #define BYTE_ORDER      BIG_ENDIAN      /* byte order we use on ppc */
  41 #define ENDIAN          BIG
  42 #else
  43 #error code has not been ported to little endian targets yet
  44 #endif
  45
  46 /*
  47  * Macros for network/external number representation conversion.
  48  */
  49 #if BYTE_ORDER == BIG_ENDIAN && !defined(lint)
  50 #define ntohl(x)        (x)
  51 #define ntohs(x)        (x)
  52 #define htonl(x)        (x)
  53 #define htons(x)        (x)
  54
  55 static __inline__ unsigned int byte_reverse_word(unsigned int word);
  56 static __inline__ unsigned int byte_reverse_word(unsigned int word) {
  57         unsigned int result;
  58         __asm__ volatile("lwbrx %0, 0, %1" : "=r" (result) : "r" (&word));
  59         return result;
  60 }
  61
  62 /* The above function is commutative, so we can use it for
  63  * translations in both directions (to/from little endianness)
  64  * Note that htolx and ltohx are probably identical, they are
  65  * included for completeness.
  66  */
  67 #define htoll(x)  byte_reverse_word(x)
  68 #define htols(x)  (byte_reverse_word(x) >> 16)
  69 #define ltohl(x)  htoll(x)
  70 #define ltohs(x)  htols(x)
  71
  72 #define htobl(x) (x)
  73 #define htobs(x) (x)
  74 #define btohl(x) (x)
  75 #define btohs(x) (x)
  76
  77 #else
  78 unsigned short  ntohs(), htons();
  79 unsigned long   ntohl(), htonl();
  80 #endif
  81
  82 /* This defines the order of elements in a bitfield,
  83  * it is principally used by the SCSI subsystem in
  84  * the definitions of mapped registers
  85  */
  86 #define BYTE_MSF 1
  87
  88 #endif /* _MACHINE_ENDIAN_H_ */