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Annotation of XNU/osfmk/ppc/endian.h, revision 1.1.1.1

1.1       root        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: #if _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_ */

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