osfmk/ppc/endian.h

   1 /*
   2  * Copyright (c) 2000 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 #ifdef __BIG_ENDIAN__                   /* Predefined by compiler */
  45 #define BYTE_ORDER      BIG_ENDIAN      /* byte order we use on ppc */
  46 #define ENDIAN          BIG
  47 #else
  48 #error code has not been ported to little endian targets yet
  49 #endif
  50
  51 /*
  52  * Macros for network/external number representation conversion.
  53  */
  54 #if BYTE_ORDER == BIG_ENDIAN && !defined(lint)
  55 #define ntohl(x)        (x)
  56 #define ntohs(x)        (x)
  57 #define htonl(x)        (x)
  58 #define htons(x)        (x)
  59
  60 static __inline__ unsigned int byte_reverse_word(unsigned int word);
  61 static __inline__ unsigned int byte_reverse_word(unsigned int word) {
  62         unsigned int result;
  63         __asm__ volatile("lwbrx %0, 0, %1" : "=r" (result) : "r" (&word));
  64         return result;
  65 }
  66
  67 /* The above function is commutative, so we can use it for
  68  * translations in both directions (to/from little endianness)
  69  * Note that htolx and ltohx are probably identical, they are
  70  * included for completeness.
  71  */
  72 #define htoll(x)  byte_reverse_word(x)
  73 #define htols(x)  (byte_reverse_word(x) >> 16)
  74 #define ltohl(x)  htoll(x)
  75 #define ltohs(x)  htols(x)
  76
  77 #define htobl(x) (x)
  78 #define htobs(x) (x)
  79 #define btohl(x) (x)
  80 #define btohs(x) (x)
  81
  82 #else
  83 unsigned short  ntohs(), htons();
  84 unsigned long   ntohl(), htonl();
  85 #endif
  86
  87 /* This defines the order of elements in a bitfield,
  88  * it is principally used by the SCSI subsystem in
  89  * the definitions of mapped registers
  90  */
  91 #define BYTE_MSF 1
  92
  93 #endif /* _MACHINE_ENDIAN_H_ */