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 1.3 2007/06/19 23:47:18 tbox Exp $ */ 18258945Sroberto 19258945Sroberto#ifndef ISC_ATOMIC_H 20258945Sroberto#define ISC_ATOMIC_H 1 21258945Sroberto 22258945Sroberto#include <isc/platform.h> 23258945Sroberto#include <isc/types.h> 24258945Sroberto 25258945Sroberto#ifdef ISC_PLATFORM_USEGCCASM 26258945Sroberto/* 27258945Sroberto * This routine atomically increments the value stored in 'p' by 'val', and 28258945Sroberto * returns the previous value. 29258945Sroberto */ 30258945Srobertostatic inline isc_int32_t 31258945Srobertoisc_atomic_xadd(isc_int32_t *p, int val) { 32258945Sroberto isc_int32_t orig; 33258945Sroberto 34258945Sroberto /* add is a cheat, since MIPS has no mov instruction */ 35258945Sroberto __asm__ volatile ( 36258945Sroberto "1:" 37258945Sroberto "ll $3, %1\n" 38258945Sroberto "add %0, $0, $3\n" 39258945Sroberto "add $3, $3, %2\n" 40258945Sroberto "sc $3, %1\n" 41258945Sroberto "beq $3, 0, 1b" 42258945Sroberto : "=&r"(orig) 43258945Sroberto : "m"(*p), "r"(val) 44258945Sroberto : "memory", "$3" 45258945Sroberto ); 46258945Sroberto 47258945Sroberto return (orig); 48258945Sroberto} 49258945Sroberto 50258945Sroberto/* 51258945Sroberto * This routine atomically stores the value 'val' in 'p'. 52258945Sroberto */ 53258945Srobertostatic inline void 54258945Srobertoisc_atomic_store(isc_int32_t *p, isc_int32_t val) { 55258945Sroberto __asm__ volatile ( 56258945Sroberto "1:" 57258945Sroberto "ll $3, %0\n" 58258945Sroberto "add $3, $0, %1\n" 59258945Sroberto "sc $3, %0\n" 60258945Sroberto "beq $3, 0, 1b" 61258945Sroberto : 62258945Sroberto : "m"(*p), "r"(val) 63258945Sroberto : "memory", "$3" 64258945Sroberto ); 65258945Sroberto} 66258945Sroberto 67258945Sroberto/* 68258945Sroberto * This routine atomically replaces the value in 'p' with 'val', if the 69258945Sroberto * original value is equal to 'cmpval'. The original value is returned in any 70258945Sroberto * case. 71258945Sroberto */ 72258945Srobertostatic inline isc_int32_t 73258945Srobertoisc_atomic_cmpxchg(isc_int32_t *p, int cmpval, int val) { 74258945Sroberto isc_int32_t orig; 75258945Sroberto 76258945Sroberto __asm__ volatile( 77258945Sroberto "1:" 78258945Sroberto "ll $3, %1\n" 79258945Sroberto "add %0, $0, $3\n" 80258945Sroberto "bne $3, %2, 2f\n" 81258945Sroberto "add $3, $0, %3\n" 82258945Sroberto "sc $3, %1\n" 83258945Sroberto "beq $3, 0, 1b\n" 84258945Sroberto "2:" 85258945Sroberto : "=&r"(orig) 86258945Sroberto : "m"(*p), "r"(cmpval), "r"(val) 87258945Sroberto : "memory", "$3" 88258945Sroberto ); 89258945Sroberto 90258945Sroberto return (orig); 91258945Sroberto} 92258945Sroberto 93258945Sroberto#else /* !ISC_PLATFORM_USEGCCASM */ 94258945Sroberto 95258945Sroberto#error "unsupported compiler. disable atomic ops by --disable-atomic" 96258945Sroberto 97258945Sroberto#endif 98258945Sroberto#endif /* ISC_ATOMIC_H */ 99