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      1 /*	$NetBSD: atomic_swap_32_cas.c,v 1.7 2014/06/28 20:18:55 joerg Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2007 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include "atomic_op_namespace.h"
     33 
     34 #include <sys/atomic.h>
     35 
     36 uint32_t
     37 atomic_swap_32(volatile uint32_t *addr, uint32_t new)
     38 {
     39 	uint32_t old;
     40 
     41 	do {
     42 		old = *addr;
     43 	} while (atomic_cas_32(addr, old, new) != old);
     44 
     45 	return (old);
     46 }
     47 
     48 crt_alias(__atomic_exchange_4,_atomic_swap_32)
     49 
     50 #undef atomic_swap_32
     51 atomic_op_alias(atomic_swap_32,_atomic_swap_32)
     52 #undef atomic_swap_uint
     53 atomic_op_alias(atomic_swap_uint,_atomic_swap_32)
     54 __strong_alias(_atomic_swap_uint,_atomic_swap_32)
     55 crt_alias(__sync_lock_test_and_set_4,_atomic_swap_32)
     56 #if !defined(_LP64)
     57 #undef atomic_swap_ulong
     58 atomic_op_alias(atomic_swap_ulong,_atomic_swap_32)
     59 __strong_alias(_atomic_swap_ulong,_atomic_swap_32)
     60 #undef atomic_swap_ptr
     61 atomic_op_alias(atomic_swap_ptr,_atomic_swap_32)
     62 __strong_alias(_atomic_swap_ptr,_atomic_swap_32)
     63 #endif /* _LP64 */
     64