minix/common/lib/libc/arch/arm/atomic/atomic_cas_32.S
Gianluca Guida b6cbf7203b Import unmodified NetBSD libc in trunk
This patch imports the unmodified current version of NetBSD libc.
The NetBSD includes are in /nbsd_include, while the libc code itself is 
split between lib/nbsd_libc and common/lib/libc.
2011-02-14 19:36:03 +00:00

58 lines
2.4 KiB
ArmAsm

/* $NetBSD: atomic_cas_32.S,v 1.2 2008/08/16 07:12:39 matt Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas <matt@3am-software.com>
*
* 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"
#if defined(_ARM_ARCH_6)
/*
* ARMv6 has load-exclusive/store-exclusive which works for both user
* and kernel.
*/
ENTRY_NP(_atomic_cas_32)
mov r3, r0 /* we need r0 for return value */
1:
ldrex r0, [r3] /* load old value */
teq r0, r1 /* compare? */
RETc(ne) /* return if different */
strex ip, r2, [r3] /* store new value */
cmp ip, #0 /* succeed? */
bne 1b /* nope, try again. */
RET /* yes, return. */
END(_atomic_cas_32)
ATOMIC_OP_ALIAS(atomic_cas_32,_atomic_cas_32)
ATOMIC_OP_ALIAS(atomic_cas_uint,_atomic_cas_32)
ATOMIC_OP_ALIAS(atomic_cas_ulong,_atomic_cas_32)
ATOMIC_OP_ALIAS(atomic_cas_ptr,_atomic_cas_32)
STRONG_ALIAS(_atomic_cas_uint,_atomic_cas_32)
STRONG_ALIAS(_atomic_cas_ulong,_atomic_cas_32)
STRONG_ALIAS(_atomic_cas_ptr,_atomic_cas_32)
#endif /* _ARCH_ARM_6 */