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lock.h revision 1.3 
      1  1.3  thorpej /*	$NetBSD: lock.h,v 1.3 2000/04/29 19:39:51 thorpej Exp $	*/
      2  1.2  thorpej 
      3  1.2  thorpej /*-
      4  1.2  thorpej  * Copyright (c) 2000 The NetBSD Foundation, Inc.
      5  1.2  thorpej  * All rights reserved.
      6  1.2  thorpej  *
      7  1.2  thorpej  * This code is derived from software contributed to The NetBSD Foundation
      8  1.2  thorpej  * by Jason R. Thorpe.
      9  1.2  thorpej  *
     10  1.2  thorpej  * Redistribution and use in source and binary forms, with or without
     11  1.2  thorpej  * modification, are permitted provided that the following conditions
     12  1.2  thorpej  * are met:
     13  1.2  thorpej  * 1. Redistributions of source code must retain the above copyright
     14  1.2  thorpej  *    notice, this list of conditions and the following disclaimer.
     15  1.2  thorpej  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2  thorpej  *    notice, this list of conditions and the following disclaimer in the
     17  1.2  thorpej  *    documentation and/or other materials provided with the distribution.
     18  1.2  thorpej  * 3. All advertising materials mentioning features or use of this software
     19  1.2  thorpej  *    must display the following acknowledgement:
     20  1.2  thorpej  *	This product includes software developed by the NetBSD
     21  1.2  thorpej  *	Foundation, Inc. and its contributors.
     22  1.2  thorpej  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  1.2  thorpej  *    contributors may be used to endorse or promote products derived
     24  1.2  thorpej  *    from this software without specific prior written permission.
     25  1.2  thorpej  *
     26  1.2  thorpej  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  1.2  thorpej  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  1.2  thorpej  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  1.2  thorpej  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  1.2  thorpej  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  1.2  thorpej  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  1.2  thorpej  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  1.2  thorpej  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  1.2  thorpej  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  1.2  thorpej  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  1.2  thorpej  * POSSIBILITY OF SUCH DAMAGE.
     37  1.2  thorpej  */
     38  1.2  thorpej 
     39  1.2  thorpej /*
     40  1.2  thorpej  * Machine-dependent spin lock operations.
     41  1.2  thorpej  */
     42  1.2  thorpej 
     43  1.2  thorpej #ifndef _I386_LOCK_H_
     44  1.2  thorpej #define	_I386_LOCK_H_
     45  1.2  thorpej 
     46  1.2  thorpej #define	__SIMPLELOCK_LOCKED	1
     47  1.2  thorpej #define	__SIMPLELOCK_UNLOCKED	0
     48  1.3  thorpej 
     49  1.3  thorpej static __inline void __cpu_simple_lock_init __P((__volatile int *))
     50  1.3  thorpej 	__attribute__((__unused__));
     51  1.3  thorpej static __inline void __cpu_simple_lock __P((__volatile int *))
     52  1.3  thorpej 	__attribute__((__unused__));
     53  1.3  thorpej static __inline int __cpu_simple_lock_try __P((__volatile int *))
     54  1.3  thorpej 	__attribute__((__unused__));
     55  1.3  thorpej static __inline void __cpu_simple_unlock __P((__volatile int *))
     56  1.3  thorpej 	__attribute__((__unused__));
     57  1.3  thorpej 
     58  1.3  thorpej static __inline void
     59  1.3  thorpej __cpu_simple_lock_init(__volatile int *alp)
     60  1.3  thorpej {
     61  1.3  thorpej 
     62  1.3  thorpej 	*alp = __SIMPLELOCK_UNLOCKED;
     63  1.3  thorpej }
     64  1.3  thorpej 
     65  1.3  thorpej static __inline void
     66  1.3  thorpej __cpu_simple_lock(__volatile int *alp)
     67  1.3  thorpej {
     68  1.3  thorpej 	int __val = __SIMPLELOCK_LOCKED;
     69  1.3  thorpej 
     70  1.3  thorpej 	do {
     71  1.3  thorpej 		__asm __volatile("xchgl %0, %2"
     72  1.3  thorpej 			: "=r" (__val)
     73  1.3  thorpej 			: "0" (__val), "m" (*alp));
     74  1.3  thorpej 	} while (__val != __SIMPLELOCK_UNLOCKED);
     75  1.3  thorpej }
     76  1.3  thorpej 
     77  1.3  thorpej static __inline int
     78  1.3  thorpej __cpu_simple_lock_try(__volatile int *alp)
     79  1.3  thorpej {
     80  1.3  thorpej 	int __val = __SIMPLELOCK_LOCKED;
     81  1.3  thorpej 
     82  1.3  thorpej 	__asm __volatile("xchgl %0, %2"
     83  1.3  thorpej 		: "=r" (__val)
     84  1.3  thorpej 		: "0" (__val), "m" (*alp));
     85  1.3  thorpej 
     86  1.3  thorpej 	return ((__val == __SIMPLELOCK_UNLOCKED) ? 1 : 0);
     87  1.3  thorpej }
     88  1.3  thorpej 
     89  1.3  thorpej void
     90  1.3  thorpej __cpu_simple_unlock(__volatile int *alp)
     91  1.3  thorpej {
     92  1.3  thorpej 
     93  1.3  thorpej 	*alp = __SIMPLELOCK_UNLOCKED;
     94  1.3  thorpej }
     95  1.2  thorpej 
     96  1.2  thorpej #endif /* _I386_LOCK_H_ */
     97