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atomic_swap_16_cas.c revision 1.3.26.2 
      1  1.3.26.1  martin /*	$NetBSD: atomic_swap_16_cas.c,v 1.3.26.2 2020/04/21 19:37:48 martin 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