_lwp_mutex_unlock.s revision 9a70fc3be3b1e966bf78825cdb8d509963a6f0a1
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
.file "_lwp_mutex_unlock.s"
#include "SYS.h"
#include <../assym.h>
ENTRY(_lwp_mutex_unlock)
membar #LoadStore|#StoreStore
add %o0, MUTEX_LOCK_WORD, %o1
ld [%o1], %o2
1:
clr %o3 ! clear lock/get waiter field
cas [%o1], %o2, %o3 ! atomically
cmp %o2, %o3
bne,a,pn %icc, 1b
mov %o3, %o2
btst WAITER_MASK, %o3 ! check for waiters
beq,a,pt %icc,2f ! if no waiters
clr %o0 ! return 0
! else (note that %o0 is still
! &mutex)
clr %o1 ! call kernel to wakeup waiter:
SYSTRAP_RVAL1(lwp_mutex_wakeup) ! lwp_mutex_wakeup(mp, 0)
SYSLWPERR
2: RET
SET_SIZE(_lwp_mutex_unlock)