1 /* 2 * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 # include "incls/_precompiled.incl" 26 # include "incls/_atomic.cpp.incl" 27 28 jbyte Atomic::cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) { 29 assert(sizeof(jbyte) == 1, "assumption."); 30 uintptr_t dest_addr = (uintptr_t)dest; 31 uintptr_t offset = dest_addr % sizeof(jint); 32 volatile jint* dest_int = (volatile jint*)(dest_addr - offset); 33 jint cur = *dest_int; 34 jbyte* cur_as_bytes = (jbyte*)(&cur); 35 jint new_val = cur; 36 jbyte* new_val_as_bytes = (jbyte*)(&new_val); 37 new_val_as_bytes[offset] = exchange_value; 38 while (cur_as_bytes[offset] == compare_value) { 39 jint res = cmpxchg(new_val, dest_int, cur); 40 if (res == cur) break; 41 cur = res; 42 new_val = cur; 43 new_val_as_bytes[offset] = exchange_value; 44 } 45 return cur_as_bytes[offset]; 46 } 47 48 unsigned Atomic::xchg(unsigned int exchange_value, volatile unsigned int* dest) { 49 assert(sizeof(unsigned int) == sizeof(jint), "more work to do"); 50 return (unsigned int)Atomic::xchg((jint)exchange_value, (volatile jint*)dest); 51 } 52 53 unsigned Atomic::cmpxchg(unsigned int exchange_value, 54 volatile unsigned int* dest, unsigned int compare_value) { 55 assert(sizeof(unsigned int) == sizeof(jint), "more work to do"); 56 return (unsigned int)Atomic::cmpxchg((jint)exchange_value, (volatile jint*)dest, 57 (jint)compare_value); 58 }