1/*-
2 * Copyright (c) 2001 Daniel Eischen <deischen@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Neither the name of the author nor the names of its contributors
11 *    may be used to endorse or promote products derived from this software
12 *    without specific prior written permission.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#ifndef	_ATOMIC_OPS_H_
30#define	_ATOMIC_OPS_H_
31
32/*
33 * Atomic swap:
34 *   Atomic (tmp = *dst, *dst = val), then *res = tmp
35 *
36 * void atomic_swap64(intptr_t *dst, intptr_t val, intptr_t *res);
37 */
38static inline void
39atomic_swap64(volatile intptr_t *dst, intptr_t val, intptr_t *res)
40{
41	__asm __volatile(
42	"xchgq %2, %1; movq %2, %0"
43	 : "=m" (*res) : "m" (*dst), "r" (val) : "memory");
44}
45
46static inline void
47atomic_swap_int(volatile int *dst, int val, int *res)
48{
49	__asm __volatile(
50	"xchgl %2, %1; movl %2, %0"
51	 : "=m" (*res) : "m" (*dst), "r" (val) : "memory");
52}
53
54#define	atomic_swap_ptr(d, v, r) \
55	atomic_swap64((volatile intptr_t *)(d), (intptr_t)(v), (intptr_t *)(r))
56
57#endif
58