1258945Sroberto/* 2258945Sroberto * Copyright (C) 2005, 2007 Internet Systems Consortium, Inc. ("ISC") 3258945Sroberto * 4258945Sroberto * Permission to use, copy, modify, and/or distribute this software for any 5258945Sroberto * purpose with or without fee is hereby granted, provided that the above 6258945Sroberto * copyright notice and this permission notice appear in all copies. 7258945Sroberto * 8258945Sroberto * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 9258945Sroberto * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 10258945Sroberto * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 11258945Sroberto * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 12258945Sroberto * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 13258945Sroberto * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 14258945Sroberto * PERFORMANCE OF THIS SOFTWARE. 15258945Sroberto */ 16258945Sroberto 17258945Sroberto/* $Id: atomic.h,v 1.5 2007/06/19 23:47:18 tbox Exp $ */ 18258945Sroberto 19258945Sroberto/* 20258945Sroberto * This code was written based on FreeBSD's kernel source whose copyright 21258945Sroberto * follows: 22258945Sroberto */ 23258945Sroberto 24258945Sroberto/*- 25258945Sroberto * Copyright (c) 1998 Doug Rabson. 26258945Sroberto * Copyright (c) 2001 Jake Burkholder. 27258945Sroberto * All rights reserved. 28258945Sroberto * 29258945Sroberto * Redistribution and use in source and binary forms, with or without 30258945Sroberto * modification, are permitted provided that the following conditions 31258945Sroberto * are met: 32258945Sroberto * 1. Redistributions of source code must retain the above copyright 33258945Sroberto * notice, this list of conditions and the following disclaimer. 34258945Sroberto * 2. Redistributions in binary form must reproduce the above copyright 35258945Sroberto * notice, this list of conditions and the following disclaimer in the 36258945Sroberto * documentation and/or other materials provided with the distribution. 37258945Sroberto * 38258945Sroberto * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 39258945Sroberto * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 40258945Sroberto * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 41258945Sroberto * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 42258945Sroberto * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 43258945Sroberto * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 44258945Sroberto * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 45258945Sroberto * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 46258945Sroberto * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 47258945Sroberto * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 48258945Sroberto * SUCH DAMAGE. 49258945Sroberto * 50258945Sroberto * from: FreeBSD: src/sys/i386/include/atomic.h,v 1.20 2001/02/11 51280849Scy * $FreeBSD: 258945 2013-12-04 21:33:17Z roberto $ 52258945Sroberto */ 53258945Sroberto 54258945Sroberto#ifndef ISC_ATOMIC_H 55258945Sroberto#define ISC_ATOMIC_H 1 56258945Sroberto 57258945Sroberto#include <isc/platform.h> 58258945Sroberto#include <isc/types.h> 59258945Sroberto 60258945Sroberto#define ASI_P 0x80 /* Primary Address Space Identifier */ 61258945Sroberto 62258945Sroberto#ifdef ISC_PLATFORM_USEGCCASM 63258945Sroberto 64258945Sroberto/* 65258945Sroberto * This routine atomically increments the value stored in 'p' by 'val', and 66258945Sroberto * returns the previous value. 67258945Sroberto */ 68258945Srobertostatic inline isc_int32_t 69258945Srobertoisc_atomic_xadd(isc_int32_t *p, isc_int32_t val) { 70258945Sroberto isc_int32_t prev, swapped; 71258945Sroberto 72258945Sroberto for (prev = *(volatile isc_int32_t *)p; ; prev = swapped) { 73258945Sroberto swapped = prev + val; 74258945Sroberto __asm__ volatile( 75258945Sroberto "casa [%1] %2, %3, %0" 76258945Sroberto : "+r"(swapped) 77258945Sroberto : "r"(p), "n"(ASI_P), "r"(prev)); 78258945Sroberto if (swapped == prev) 79258945Sroberto break; 80258945Sroberto } 81258945Sroberto 82258945Sroberto return (prev); 83258945Sroberto} 84258945Sroberto 85258945Sroberto/* 86258945Sroberto * This routine atomically stores the value 'val' in 'p'. 87258945Sroberto */ 88258945Srobertostatic inline void 89258945Srobertoisc_atomic_store(isc_int32_t *p, isc_int32_t val) { 90258945Sroberto isc_int32_t prev, swapped; 91258945Sroberto 92258945Sroberto for (prev = *(volatile isc_int32_t *)p; ; prev = swapped) { 93258945Sroberto swapped = val; 94258945Sroberto __asm__ volatile( 95258945Sroberto "casa [%1] %2, %3, %0" 96258945Sroberto : "+r"(swapped) 97258945Sroberto : "r"(p), "n"(ASI_P), "r"(prev) 98258945Sroberto : "memory"); 99258945Sroberto if (swapped == prev) 100258945Sroberto break; 101258945Sroberto } 102258945Sroberto} 103258945Sroberto 104258945Sroberto/* 105258945Sroberto * This routine atomically replaces the value in 'p' with 'val', if the 106258945Sroberto * original value is equal to 'cmpval'. The original value is returned in any 107258945Sroberto * case. 108258945Sroberto */ 109258945Srobertostatic inline isc_int32_t 110258945Srobertoisc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) { 111258945Sroberto isc_int32_t temp = val; 112258945Sroberto 113258945Sroberto __asm__ volatile( 114258945Sroberto "casa [%1] %2, %3, %0" 115258945Sroberto : "+r"(temp) 116258945Sroberto : "r"(p), "n"(ASI_P), "r"(cmpval)); 117258945Sroberto 118258945Sroberto return (temp); 119258945Sroberto} 120258945Sroberto 121258945Sroberto#else /* ISC_PLATFORM_USEGCCASM */ 122258945Sroberto 123258945Sroberto#error "unsupported compiler. disable atomic ops by --disable-atomic" 124258945Sroberto 125258945Sroberto#endif /* ISC_PLATFORM_USEGCCASM */ 126258945Sroberto 127258945Sroberto#endif /* ISC_ATOMIC_H */ 128