minix/common/lib/libc/atomic/atomic_swap_64_cas.c

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/* $NetBSD: atomic_swap_64_cas.c,v 1.5 2008/04/28 20:22:53 martin Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* 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. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include "atomic_op_namespace.h"
#include <sys/atomic.h>
#ifdef __HAVE_ATOMIC64_OPS
uint64_t
atomic_swap_64(volatile uint64_t *addr, uint64_t new)
{
uint64_t old;
do {
old = *addr;
} while (atomic_cas_64(addr, old, new) != old);
return (old);
}
#undef atomic_swap_64
atomic_op_alias(atomic_swap_64,_atomic_swap_64)
#if defined(_LP64)
#undef atomic_swap_ulong
atomic_op_alias(atomic_swap_ulong,_atomic_swap_64)
__strong_alias(_atomic_swap_ulong,_atomic_swap_64)
#undef atomic_swap_ptr
atomic_op_alias(atomic_swap_ptr,_atomic_swap_64)
__strong_alias(_atomic_swap_ptr,_atomic_swap_64)
#endif /* _LP64 */
#endif