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/*-
* Copyright (c) 2003 Jake Burkholder <jake@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _ATOMIC_OPS_H_
#define _ATOMIC_OPS_H_
#include <machine/atomic.h>
/*
* Atomic swap:
* Atomic (tmp = *dst, *dst = val), then *res = tmp
*
* void atomic_swap_long(long *dst, long val, long *res);
*/
static __inline void
atomic_swap_long(volatile long *dst, long val, long *res)
{
long tmp;
long r;
tmp = *dst;
for (;;) {
r = atomic_cas_64(dst, tmp, val);
if (r == tmp)
break;
tmp = r;
}
*res = tmp;
}
static __inline void
atomic_swap_int(volatile int *dst, int val, int *res)
{
int tmp;
int r;
tmp = *dst;
for (;;) {
r = atomic_cas_32(dst, tmp, val);
if (r == tmp)
break;
tmp = r;
}
*res = tmp;
}
#define atomic_swap_ptr(dst, val, res) \
atomic_swap_long((volatile long *)dst, (long)val, (long *)res)
#endif
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