LCOM1920-T02G10

/*        $NetBSD: rwlock.h,v 1.5 2008/04/28 20:23:40 martin Exp $        */

/*-

 * Copyright (c) 2002, 2006 The NetBSD Foundation, Inc.

 * All rights reserved.

 *

 * This code is derived from software contributed to The NetBSD Foundation

 * by Jason R. Thorpe and Andrew Doran.

 *

 * 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.

 */

#ifndef _X86_RWLOCK_H_

#define        _X86_RWLOCK_H_

struct krwlock {

        volatile uintptr_t        rw_owner;

};

#ifdef __RWLOCK_PRIVATE

#define        __HAVE_SIMPLE_RW_LOCKS                1

#define        __HAVE_RW_STUBS                        1

/*

 * RW_RECEIVE: no memory barrier required, as 'ret' implies a load fence. 

 */

#define        RW_RECEIVE(rw)                        /* nothing */

/*

 * RW_GIVE: no memory barrier required, as _lock_cas() will take care of it.

 */

#define        RW_GIVE(rw)                        /* nothing */

#define        RW_CAS(p, o, n)                        \

    (_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))

unsigned long        _atomic_cas_ulong(volatile unsigned long *,

    unsigned long, unsigned long);

#endif        /* __RWLOCK_PRIVATE */

#endif /* _X86_RWLOCK_H_ */