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/*-
* Copyright (c) 2003 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.
*
* $FreeBSD$
*/
#ifndef _ATOMIC_OPS_H_
#define _ATOMIC_OPS_H_
/*
* Atomic swap:
* Atomic (tmp = *dst, *dst = val), then *res = tmp
*
* void atomic_swap_long(long *dst, long val, long *res);
*/
static inline void
atomic_swap_long(long *dst, long val, long *res)
{
/* $1 and $2 are t0 and t1 respectively. */
__asm __volatile (
" ldq $1, %1\n" /* get cache line before lock */
"1: ldq_l $1, %1\n" /* load *dst asserting lock */
" mov %2, $2\n" /* save value to be swapped */
" stq_c $2, %1\n" /* attempt the store; $2 clobbered */
" beq $2, 1b\n" /* it didn't work, loop */
" stq $1, %0\n" /* save value of *dst in *res */
" mb \n"
: "+m"(*res)
: "m"(*dst), "r"(val)
: "memory", "$1", "$2"); /* clobber t0 and t1 */
}
static inline void
atomic_swap_int(int *dst, int val, int *res)
{
/* $1 and $2 are t0 and t1 respectively. */
__asm __volatile (
" ldl $1, %1\n" /* get cache line before lock */
"1: ldl_l $1, %1\n" /* load *dst asserting lock */
" mov %2, $2\n" /* save value to be swapped */
" stl_c $2, %1\n" /* attempt the store; $2 clobbered */
" beq $2, 1b\n" /* it didn't work, loop */
" stl $1, %0\n" /* save value of *dst in *res */
" mb \n"
: "+m"(*res)
: "m"(*dst), "r"(val)
: "memory", "$1", "$2"); /* clobber t0 and t1 */
}
#define atomic_swap_ptr(d, v, r) \
atomic_swap_long((long *)(d), (long)(v), (long *)(r))
#endif
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