1 /* $OpenBSD: atomic.h,v 1.6 2007/05/25 15:55:27 art Exp $ */
2 /* $NetBSD: atomic.h,v 1.1.2.2 2000/02/21 18:54:07 sommerfeld Exp $ */
3
4 /*-
5 * Copyright (c) 2000 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by RedBack Networks Inc.
10 *
11 * Author: Bill Sommerfeld
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 * must display the following acknowledgement:
23 * This product includes software developed by the NetBSD
24 * Foundation, Inc. and its contributors.
25 * 4. Neither the name of The NetBSD Foundation nor the names of its
26 * contributors may be used to endorse or promote products derived
27 * from this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
30 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
31 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
32 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
33 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
34 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
35 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
39 * POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #ifndef _I386_ATOMIC_H_
43 #define _I386_ATOMIC_H_
44
45 /*
46 * Perform atomic operations on memory. Should be atomic with respect
47 * to interrupts and multiple processors.
48 *
49 * void atomic_setbits_int(volatile u_int *a, u_int mask) { *a |= mask; }
50 * void atomic_clearbits_int(volatile u_int *a, u_int mas) { *a &= ~mask; }
51 */
52 #if defined(_KERNEL) && !defined(_LOCORE)
53
54 #ifdef MULTIPROCESSOR
55 #define LOCK "lock"
56 #else
57 #define LOCK
58 #endif
59
60 static __inline u_int64_t
61 i386_atomic_testset_uq(volatile u_int64_t *ptr, u_int64_t val)
62 {
63 __asm__ volatile ("\n1:\t" LOCK " cmpxchg8b (%1); jnz 1b" : "+A" (val) :
64 "r" (ptr), "b" ((u_int32_t)val), "c" ((u_int32_t)(val >> 32)));
65 return val;
66 }
67
68 static __inline u_int32_t
69 i386_atomic_testset_ul(volatile u_int32_t *ptr, unsigned long val)
70 {
71 __asm__ volatile ("xchgl %0,(%2)" :"=r" (val):"0" (val),"r" (ptr));
72 return val;
73 }
74
75 static __inline int
76 i386_atomic_testset_i(volatile int *ptr, unsigned long val)
77 {
78 __asm__ volatile ("xchgl %0,(%2)" :"=r" (val):"0" (val),"r" (ptr));
79 return val;
80 }
81
82 static __inline void
83 i386_atomic_setbits_l(volatile u_int32_t *ptr, unsigned long bits)
84 {
85 __asm __volatile(LOCK " orl %1,%0" : "=m" (*ptr) : "ir" (bits));
86 }
87
88 static __inline void
89 i386_atomic_clearbits_l(volatile u_int32_t *ptr, unsigned long bits)
90 {
91 bits = ~bits;
92 __asm __volatile(LOCK " andl %1,%0" : "=m" (*ptr) : "ir" (bits));
93 }
94
95 /*
96 * cas = compare and set
97 */
98 static __inline int
99 i486_atomic_cas_int(volatile u_int *ptr, u_int expect, u_int set)
100 {
101 int res;
102
103 __asm volatile(LOCK " cmpxchgl %2, %1" : "=a" (res), "=m" (*ptr)
104 : "r" (set), "a" (expect), "m" (*ptr) : "memory");
105
106 return (res);
107 }
108
109 #define atomic_setbits_int i386_atomic_setbits_l
110 #define atomic_clearbits_int i386_atomic_clearbits_l
111
112 #undef LOCK
113
114 #endif /* defined(_KERNEL) && !defined(_LOCORE) */
115 #endif /* _I386_ATOMIC_H_ */