osfmk/ppc/endian.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  * @OSF_COPYRIGHT@
  32  *
  33  */
  34
  35 #ifndef _MACHINE_ENDIAN_H_
  36 #define _MACHINE_ENDIAN_H_
  37
  38 /*
  39  * Definitions for byte order,
  40  * according to byte significance from low address to high.
  41  */
  42 #define LITTLE_ENDIAN   1234    /* least-significant byte first (vax) */
  43 #define BIG_ENDIAN      4321    /* most-significant byte first (IBM, net) */
  44 #define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp) */
  45
  46 #ifdef __BIG_ENDIAN__                   /* Predefined by compiler */
  47 #define BYTE_ORDER      BIG_ENDIAN      /* byte order we use on ppc */
  48 #define ENDIAN          BIG
  49 #else
  50 #error code has not been ported to little endian targets yet
  51 #endif
  52
  53 /*
  54  * Macros for network/external number representation conversion.
  55  */
  56 #if BYTE_ORDER == BIG_ENDIAN && !defined(lint)
  57 #define ntohl(x)        (x)
  58 #define ntohs(x)        (x)
  59 #define htonl(x)        (x)
  60 #define htons(x)        (x)
  61
  62 static __inline__ unsigned int byte_reverse_word(unsigned int word);
  63 static __inline__ unsigned int byte_reverse_word(unsigned int word) {
  64         unsigned int result;
  65         __asm__ volatile("lwbrx %0, 0, %1" : "=r" (result) : "r" (&word));
  66         return result;
  67 }
  68
  69 /* The above function is commutative, so we can use it for
  70  * translations in both directions (to/from little endianness)
  71  * Note that htolx and ltohx are probably identical, they are
  72  * included for completeness.
  73  */
  74 #define htoll(x)  byte_reverse_word(x)
  75 #define htols(x)  (byte_reverse_word(x) >> 16)
  76 #define ltohl(x)  htoll(x)
  77 #define ltohs(x)  htols(x)
  78
  79 #define htobl(x) (x)
  80 #define htobs(x) (x)
  81 #define btohl(x) (x)
  82 #define btohs(x) (x)
  83
  84 #else
  85 unsigned short  ntohs(), htons();
  86 unsigned long   ntohl(), htonl();
  87 #endif
  88
  89 /* This defines the order of elements in a bitfield,
  90  * it is principally used by the SCSI subsystem in
  91  * the definitions of mapped registers
  92  */
  93 #define BYTE_MSF 1
  94
  95 #endif /* _MACHINE_ENDIAN_H_ */