#ifndef _M88K_LOCK_H_
#define _M88K_LOCK_H_
/*      $OpenBSD: lock.h,v 1.11 2015/02/11 00:14:11 dlg Exp $   */

/*
 * Copyright (c) 2005, Miodrag Vallat.
 *
 * 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 AUTHOR ``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 AUTHOR 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 <m88k/asm.h>

typedef volatile u_int  __cpu_simple_lock_t;

/* do not change these - code below assumes r0 == __SIMPLELOCK_UNLOCKED */
#define __SIMPLELOCK_LOCKED     1
#define __SIMPLELOCK_UNLOCKED   0

static __inline__ void
__cpu_simple_lock_init(__cpu_simple_lock_t *l)
{
        *l = __SIMPLELOCK_UNLOCKED;
}

static __inline__ int
__cpu_simple_lock_try(__cpu_simple_lock_t *l)
{
        /*
         * The local __cpu_simple_lock_t is not declared volatile, so that
         * there are not pipeline synchronization around stores to it.
         * xmem will do the right thing regardless of the volatile qualifier.
         */
        u_int old = __SIMPLELOCK_LOCKED;

        __asm__ volatile
            ("xmem %0, %2, %%r0" : "+r"(old), "+m"(*l) : "r"(l));

        return (old == __SIMPLELOCK_UNLOCKED);
}

static __inline__ void
__cpu_simple_lock(__cpu_simple_lock_t *l)
{
        for (;;) {
                if (__cpu_simple_lock_try(l) != 0)
                        break;
                while (*l != __SIMPLELOCK_UNLOCKED)
                        ;       /* spin without exclusive bus access */
        }
}

static __inline__ void
__cpu_simple_unlock(__cpu_simple_lock_t *l)
{
        *l = __SIMPLELOCK_UNLOCKED;
}

#endif  /* _M88K_LOCK_H_ */