xnu-201.19.tar.gz

[apple/xnu.git] / libkern / i386 / OSAtomic.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
 /*
 * Copyright (c) 1999 Apple Computer, Inc.
 *
 *
 * HISTORY
 *
 * wgulland  23 Jul 99 - Bogus implementation!
 */
#include <libkern/OSAtomic.h>

#warning Bogus OSCompareAndSwap() for i386
int OSCompareAndSwap( UInt32 oldVal,
	UInt32 newVal, UInt32 * addr )
{
    /*
     * This should be
     * EAX = oldVal
     * Lock:CMPXCHG addr, newVal
     * But I don't know how to write that.
     */
    int ok;
    if( (ok = (oldVal == *addr)))
        *addr = newVal;
    return( ok );
}