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Annotation of XNU/libkern/i386/OSAtomic.c, 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:  * 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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