xref: /freebsd-10.3-release/lib/libkse/arch/arm/include/atomic_ops.h

/*-
 * Copyright (c) 2001 Daniel Eischen <deischen@FreeBSD.org>
 * 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. Neither the name of the author nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * 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.
 *
 * $FreeBSD: head/lib/libkse/arch/arm/include/atomic_ops.h 129206 2004-05-14 12:21:29Z cognet $
 */

#ifndef	_ATOMIC_OPS_H_
#define	_ATOMIC_OPS_H_

/*
 * Atomic swap:
 *   Atomic (tmp = *dst, *dst = val), then *res = tmp
 *
 * void atomic_swap32(intptr_t *dst, intptr_t val, intptr_t *res);
 */
static inline void
atomic_swap32(intptr_t *dst, intptr_t val, intptr_t *res)
{
	__asm __volatile(
	"swp %2, %2, [%1]; mov %2, %0"
	 : "=r" (*res) : "r" (dst), "r" (val) : "cc");
}

#define	atomic_swap_ptr(d, v, r) \
	atomic_swap32((intptr_t *)d, (intptr_t)v, (intptr_t *)r)

#define	atomic_swap_int(d, v, r) \
	atomic_swap32((intptr_t *)d, (intptr_t)v, (intptr_t *)r)
#endif