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Annotation of XNU/libkern/i386/OSAtomic.c, 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:  * Copyright (c) 1999 Apple Computer, Inc.
        !            24:  *
        !            25:  *
        !            26:  * HISTORY
        !            27:  *
        !            28:  * wgulland  23 Jul 99 - Bogus implementation!
        !            29:  */
        !            30: #include <libkern/OSAtomic.h>
        !            31: 
        !            32: #warning Bogus OSCompareAndSwap() for i386
        !            33: int OSCompareAndSwap( UInt32 oldVal,
        !            34:        UInt32 newVal, UInt32 * addr )
        !            35: {
        !            36:     /*
        !            37:      * This should be
        !            38:      * EAX = oldVal
        !            39:      * Lock:CMPXCHG addr, newVal
        !            40:      * But I don't know how to write that.
        !            41:      */
        !            42:     int ok;
        !            43:     if( (ok = (oldVal == *addr)))
        !            44:         *addr = newVal;
        !            45:     return( ok );
        !            46: }
        !            47: 

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