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atomic_swap.S revision 1.6 
      1 /*	$NetBSD: atomic_swap.S,v 1.6 2013/07/16 23:24:18 matt 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_asm.h"
     33 
     34 	.text
     35 
     36 ENTRY(_atomic_swap_32)
     37 	movl	4(%sp), %a0
     38 1:	movl	(%a0), %d0
     39 	movl	8(%sp), %d1
     40 	casl	%d0, %d1, (%a0)
     41 	bne	1b
     42 	/* %d0 now contains the old value */
     43 	movl	%d0, %a0	/* pointers return also in %a0 */
     44 	rts
     45 END(_atomic_swap_32)
     46 ATOMIC_OP_ALIAS(atomic_swap_32,_atomic_swap_32)
     47 ATOMIC_OP_ALIAS(atomic_swap_uint,_atomic_swap_32)
     48 STRONG_ALIAS(_atomic_swap_uint,_atomic_swap_32)
     49 ATOMIC_OP_ALIAS(atomic_swap_ulong,_atomic_swap_32)
     50 STRONG_ALIAS(_atomic_swap_ulong,_atomic_swap_32)
     51 ATOMIC_OP_ALIAS(atomic_swap_ptr,_atomic_swap_32)
     52 STRONG_ALIAS(_atomic_swap_ptr,_atomic_swap_32)
     53