minix/common/lib/libc/arch/arm/atomic/atomic_swap_64.S

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/* $NetBSD: atomic_swap_64.S,v 1.7 2013/11/30 21:09:11 joerg Exp $ */
/*-
* Copyright (c) 2012 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas.
*
* 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.
*
* 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"
ENTRY_NP(_atomic_swap_64)
push {r3,r4} /* save temporary */
mov ip, r0 /* return value will be in r0 */
#ifndef __ARM_EABI__
mov r3, r2 /* r2 will be overwriten by r1 */
mov r2, r1 /* and r1 will be overwritten by ldrexd */
#endif
1: ldrexd r0, r1, [ip] /* load old value */
strexd r4, r2, r3, [ip] /* store new value */
cmp r4, #0 /* succeed? */
bne 1b /* no, try again */
#ifdef _ARM_ARCH_7
dmb
#else
mcr p15, 0, r4, c7, c10, 5 /* data memory barrier */
#endif
pop {r3,r4} /* restore temporary */
RET
END(_atomic_swap_64)
ATOMIC_OP_ALIAS(atomic_swap_64,_atomic_swap_64)
STRONG_ALIAS(__sync_lock_test_and_set_8,_atomic_swap_64)
ENTRY_NP(__sync_lock_release_8)
mov r2, #0
mov r3, #0
strd r2, r3, [r0]
RET
END(__sync_lock_release_8)