lock.h revision 1.3 
1/*	$NetBSD: lock.h,v 1.3 2000/05/02 05:17:45 thorpej Exp $	*/
2
3/*-
4 * Copyright (c) 2000 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the NetBSD
21 *	Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39/*
40 * Machine-dependent spin lock operations.
41 */
42
43#ifndef _M68K_LOCK_H_
44#define	_M68K_LOCK_H_
45
46typedef	__volatile unsigned char __cpu_simple_lock_t;
47
48#define	__SIMPLELOCK_LOCKED	0x80	/* result of `tas' insn */
49#define	__SIMPLELOCK_UNLOCKED	0
50
51static __inline void __cpu_simple_lock_init __P((__cpu_simple_lock_t *))
52	__attribute__((__unused__));
53static __inline void __cpu_simple_lock __P((__cpu_simple_lock_t *))
54	__attribute__((__unused__));
55static __inline int __cpu_simple_lock_try __P((__cpu_simple_lock_t *))
56	__attribute__((__unused__));
57static __inline void __cpu_simple_unlock __P((__cpu_simple_lock_t *))
58	__attribute__((__unused__));
59
60static __inline void
61__cpu_simple_lock_init(__cpu_simple_lock_t *alp)
62{
63
64	*alp = __SIMPLELOCK_UNLOCKED;
65}
66
67static __inline void
68__cpu_simple_lock(__cpu_simple_lock_t *alp)
69{
70
71	__asm __volatile(
72		"1:	tas	%0	\n"
73		"	jne	1b	\n"
74		: "=m" (*alp));
75}
76
77static __inline int
78__cpu_simple_lock_try(__cpu_simple_lock_t *alp)
79{
80	int __rv = 1;
81
82	__asm __volatile(
83		"	tas	%0	\n"
84		"	jeq	1f	\n"
85		"	moveq	#0, %1	\n"
86		"1:			\n"
87		: "=m" (*alp), "=d" (__rv));
88
89	return (__rv);
90}
91
92static __inline void
93__cpu_simple_unlock(__cpu_simple_lock_t *alp)
94{
95
96	*alp = __SIMPLELOCK_UNLOCKED;
97}
98
99#endif /* _M68K_LOCK_H_ */
100