/*-
 * Copyright (c) 2017 Taylor R. Campbell
 * All rights reserved.
 *
 * 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 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 AUTHOR 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	UTILS_H
#define	UTILS_H

#include <sys/atomic.h>

#include <assert.h>

#define	ASSERT	assert

static inline bool
atomic_compare_exchange_weak(volatile void *ptr, void *old, void *new)
{

	return atomic_cas_ptr(ptr, old, new) == old;
}

enum memory_order {
	memory_order_acquire,
	memory_order_release,
};

static inline void
atomic_thread_fence(enum memory_order mo)
{

	switch (mo) {
	case memory_order_acquire:	membar_enter(); break;
	case memory_order_release:	membar_exit(); break;
	default:			abort();
	}
}

#define	CACHE_LINE_SIZE	64
#define	SPINLOCK_BACKOFF_MIN	1
#define	SPINLOCK_BACKOFF_MAX	1000
#define	SPINLOCK_BACKOFF(count) do { asm volatile("pause"); (count) <<= 1; } while (0)

#endif	/* UTILS_H */