1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/src/share/vm/runtime/atomic.cpp Sat Dec 01 00:00:00 2007 +0000 1.3 @@ -0,0 +1,46 @@ 1.4 +/* 1.5 + * Copyright 2001-2003 Sun Microsystems, Inc. All Rights Reserved. 1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 1.7 + * 1.8 + * This code is free software; you can redistribute it and/or modify it 1.9 + * under the terms of the GNU General Public License version 2 only, as 1.10 + * published by the Free Software Foundation. 1.11 + * 1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT 1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1.15 + * version 2 for more details (a copy is included in the LICENSE file that 1.16 + * accompanied this code). 1.17 + * 1.18 + * You should have received a copy of the GNU General Public License version 1.19 + * 2 along with this work; if not, write to the Free Software Foundation, 1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 1.21 + * 1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or 1.24 + * have any questions. 1.25 + * 1.26 + */ 1.27 + 1.28 +# include "incls/_precompiled.incl" 1.29 +# include "incls/_atomic.cpp.incl" 1.30 + 1.31 +jbyte Atomic::cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) { 1.32 + assert(sizeof(jbyte) == 1, "assumption."); 1.33 + uintptr_t dest_addr = (uintptr_t)dest; 1.34 + uintptr_t offset = dest_addr % sizeof(jint); 1.35 + volatile jint* dest_int = (volatile jint*)(dest_addr - offset); 1.36 + jint cur = *dest_int; 1.37 + jbyte* cur_as_bytes = (jbyte*)(&cur); 1.38 + jint new_val = cur; 1.39 + jbyte* new_val_as_bytes = (jbyte*)(&new_val); 1.40 + new_val_as_bytes[offset] = exchange_value; 1.41 + while (cur_as_bytes[offset] == compare_value) { 1.42 + jint res = cmpxchg(new_val, dest_int, cur); 1.43 + if (res == cur) break; 1.44 + cur = res; 1.45 + new_val = cur; 1.46 + new_val_as_bytes[offset] = exchange_value; 1.47 + } 1.48 + return cur_as_bytes[offset]; 1.49 +}