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