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 60static __inline__ unsigned int byte_reverse_word(unsigned int word); 61static __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 83unsigned short ntohs(), htons(); 84unsigned 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_ */ 94