/*
 * 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)
        movl    4(%esp), %eax
        addl    $MUTEX_LOCK_WORD, %eax
        xorl    %ecx, %ecx
        xchgl   (%eax), %ecx    / clear lock and get old lock into %ecx
        andl    $WAITER_MASK, %ecx / was anyone waiting on it?
        je      1f
        movl    0(%esp), %ecx   / prepare to call lwp_mutex_wakeup()
        movl    4(%esp), %edx
        movl    $0, 4(%esp)
        movl    %edx, 0(%esp)
        pushl   %ecx
        SYSTRAP_RVAL1(lwp_mutex_wakeup) / lwp_mutex_wakeup(mp, 0)
        popl    %ecx            / reconstruct the stack frame
        movl    0(%esp), %edx
        movl    %edx, 4(%esp)
        movl    %ecx, 0(%esp)
        SYSLWPERR
        RET
1:
        RETC
        SET_SIZE(_lwp_mutex_unlock)