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Atomic ops for 68020 and better processors.  68010 will need to use
something else for anything that uses the CAS instruction.

/*	$NetBSD: atomic_swap.S,v 1.1.2.1 2007/04/22 04:14:20 thorpej 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *      
 * 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_asm.h"

	.text

ENTRY_NOPROFILE(_atomic_swap_8)
	movl	%sp@(4), %a0
1:	movb	%a0@, %d0
	movb	%sp@(11), %d1
	casb	%d0, %d1, %a0@
	bne	1b
	/* %d0[7..0] now contains the old value */
	andl	#0xff, %d0
	rts
ATOMIC_OP_ALIAS(atomic_swap_8,_atomic_swap_8)
ATOMIC_OP_ALIAS(atomic_swap_uchar,_atomic_swap_8)

ENTRY_NOPROFILE(_atomic_swap_16)
	movl	%sp@(4), %a0
1:	movw	%a0@, %d0
	movw	%sp@(10), %d1
	casw	%d0, %d1, %a0@
	bne	1b
	/* %d0[15..0] now contains the old value */
	andl	#0xffff, %d0
	rts
ATOMIC_OP_ALIAS(atomic_swap_16,_atomic_swap_16)
ATOMIC_OP_ALIAS(atomic_swap_ushort,_atomic_swap_16)

ENTRY_NOPROFILE(_atomic_swap_32)
	movl	%sp@(4), %a0
1:	movl	%a0@, %d0
	movl	%sp@(8), %d1
	casl	%d0, %d1, %a0@
	bne	1b
	/* %d0 now contains the old value */
	movl	%d0, %a0	/* pointers return also in %a0 */
	rts
ATOMIC_OP_ALIAS(atomic_swap_32,_atomic_swap_32)
ATOMIC_OP_ALIAS(atomic_swap_uint,_atomic_swap_32)
ATOMIC_OP_ALIAS(atomic_swap_ulong,_atomic_swap_32)
ATOMIC_OP_ALIAS(atomic_swap_ptr,_atomic_swap_32)