osfmk/ppc/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 #ifdef __BIG_ENDIAN__                   /* Predefined by compiler */
  39 #define BYTE_ORDER      BIG_ENDIAN      /* byte order we use on ppc */
  40 #define ENDIAN          BIG
  41 #else
  42 #error code has not been ported to little endian targets yet
  43 #endif
  44
  45 /*
  46  * Macros for network/external number representation conversion.
  47  */
  48 #if BYTE_ORDER == BIG_ENDIAN && !defined(lint)
  49 #define ntohl(x)        (x)
  50 #define ntohs(x)        (x)
  51 #define htonl(x)        (x)
  52 #define htons(x)        (x)
  53
  54 static __inline__ unsigned int byte_reverse_word(unsigned int word);
  55 static __inline__ unsigned int byte_reverse_word(unsigned int word) {
  56         unsigned int result;
  57         __asm__ volatile("lwbrx %0, 0, %1" : "=r" (result) : "r" (&word));
  58         return result;
  59 }
  60
  61 /* The above function is commutative, so we can use it for
  62  * translations in both directions (to/from little endianness)
  63  * Note that htolx and ltohx are probably identical, they are
  64  * included for completeness.
  65  */
  66 #define htoll(x)  byte_reverse_word(x)
  67 #define htols(x)  (byte_reverse_word(x) >> 16)
  68 #define ltohl(x)  htoll(x)
  69 #define ltohs(x)  htols(x)
  70
  71 #define htobl(x) (x)
  72 #define htobs(x) (x)
  73 #define btohl(x) (x)
  74 #define btohs(x) (x)
  75
  76 #else
  77 unsigned short  ntohs(), htons();
  78 unsigned long   ntohl(), htonl();
  79 #endif
  80
  81 /* This defines the order of elements in a bitfield,
  82  * it is principally used by the SCSI subsystem in
  83  * the definitions of mapped registers
  84  */
  85 #define BYTE_MSF 1
  86
  87 #endif /* _MACHINE_ENDIAN_H_ */