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      1  1.3   joerg /*	$NetBSD: atomic_swap_16_cas.c,v 1.3 2014/06/28 20:18:55 joerg Exp $	*/
      2  1.2  martin 
      3  1.2  martin /*-
      4  1.2  martin  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  1.2  martin  * All rights reserved.
      6  1.2  martin  *
      7  1.2  martin  * This code is derived from software contributed to The NetBSD Foundation
      8  1.2  martin  * by Jason R. Thorpe.
      9  1.2  martin  *
     10  1.2  martin  * Redistribution and use in source and binary forms, with or without
     11  1.2  martin  * modification, are permitted provided that the following conditions
     12  1.2  martin  * are met:
     13  1.2  martin  * 1. Redistributions of source code must retain the above copyright
     14  1.2  martin  *    notice, this list of conditions and the following disclaimer.
     15  1.2  martin  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2  martin  *    notice, this list of conditions and the following disclaimer in the
     17  1.2  martin  *    documentation and/or other materials provided with the distribution.
     18  1.2  martin  *
     19  1.2  martin  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.2  martin  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.2  martin  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.2  martin  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.2  martin  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.2  martin  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.2  martin  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.2  martin  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.2  martin  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.2  martin  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.2  martin  * POSSIBILITY OF SUCH DAMAGE.
     30  1.2  martin  */
     31  1.2  martin 
     32  1.2  martin #include "atomic_op_namespace.h"
     33  1.2  martin 
     34  1.2  martin #include <sys/atomic.h>
     35  1.2  martin 
     36  1.2  martin uint16_t
     37  1.2  martin atomic_swap_16(volatile uint16_t *addr, uint16_t new)
     38  1.2  martin 	asm("__sync_lock_test_and_set_2");
     39  1.2  martin 
     40  1.2  martin uint16_t
     41  1.2  martin atomic_swap_16(volatile uint16_t *addr, uint16_t new)
     42  1.2  martin {
     43  1.2  martin 	uint16_t old;
     44  1.2  martin 
     45  1.2  martin 	do {
     46  1.2  martin 		old = *addr;
     47  1.2  martin 	} while (atomic_cas_16(addr, old, new) != old);
     48  1.2  martin 
     49  1.2  martin 	return old;
     50  1.2  martin }
     51  1.3   joerg 
     52  1.3   joerg crt_alias(__atomic_exchange_2,__sync_lock_test_and_set_2)
     53