atomic_ops.h revision 132400
1/* 2 * Copyright 2004 by Peter Grehan. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. The name of the author may not be used to endorse or promote products 13 * derived from this software without specific prior written permission. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 20 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 21 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 22 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD: head/lib/libkse/arch/powerpc/include/atomic_ops.h 132400 2004-07-19 12:19:04Z grehan $ 28 */ 29 30#ifndef _ATOMIC_OPS_H_ 31#define _ATOMIC_OPS_H_ 32 33/* 34 * Atomic swap: 35 * Atomic (tmp = *dst, *dst = val), then *res = tmp 36 * 37 * void atomic_swap32(intptr_t *dst, intptr_t val, intptr_t *res); 38 */ 39static inline void 40atomic_swap32(intptr_t *dst, intptr_t val, intptr_t *res) 41{ 42 int tmp; 43 44 tmp = 0; /* should be a better way to quieten cc1... */ 45#ifdef __GNUC__ 46 __asm __volatile( 47 "1: lwarx %0, 0, %4\n" /* load with reservation */ 48 " stwcx. %3, 0, %4\n" /* attempt to store val */ 49 " bne- 1b\n" /* interrupted? retry */ 50 " stw %0, %1\n" /* else, *dst -> *res */ 51 : "=&r" (tmp), "=m" (*res), "+m" (*dst) 52 : "r" (val), "r" (dst) 53 : "cc", "memory"); 54#endif 55} 56 57#define atomic_swap_ptr(d, v, r) \ 58 atomic_swap32((intptr_t *)d, (intptr_t)v, (intptr_t *)r) 59 60#define atomic_swap_int(d, v, r) \ 61 atomic_swap32((intptr_t *)d, (intptr_t)v, (intptr_t *)r) 62#endif 63