duke@435: /*
stefank@2314:  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "runtime/atomic.hpp"
stefank@2314: #ifdef TARGET_OS_FAMILY_linux
stefank@2314: # include "os_linux.inline.hpp"
stefank@2314: #endif
stefank@2314: #ifdef TARGET_OS_FAMILY_solaris
stefank@2314: # include "os_solaris.inline.hpp"
stefank@2314: #endif
stefank@2314: #ifdef TARGET_OS_FAMILY_windows
stefank@2314: # include "os_windows.inline.hpp"
stefank@2314: #endif
never@3156: #ifdef TARGET_OS_FAMILY_bsd
never@3156: # include "os_bsd.inline.hpp"
never@3156: #endif
twisti@4318: 
twisti@4318: #include "runtime/atomic.inline.hpp"
duke@435: 
duke@435: jbyte Atomic::cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) {
duke@435:   assert(sizeof(jbyte) == 1, "assumption.");
duke@435:   uintptr_t dest_addr = (uintptr_t)dest;
duke@435:   uintptr_t offset = dest_addr % sizeof(jint);
duke@435:   volatile jint* dest_int = (volatile jint*)(dest_addr - offset);
duke@435:   jint cur = *dest_int;
duke@435:   jbyte* cur_as_bytes = (jbyte*)(&cur);
duke@435:   jint new_val = cur;
duke@435:   jbyte* new_val_as_bytes = (jbyte*)(&new_val);
duke@435:   new_val_as_bytes[offset] = exchange_value;
duke@435:   while (cur_as_bytes[offset] == compare_value) {
duke@435:     jint res = cmpxchg(new_val, dest_int, cur);
duke@435:     if (res == cur) break;
duke@435:     cur = res;
duke@435:     new_val = cur;
duke@435:     new_val_as_bytes[offset] = exchange_value;
duke@435:   }
duke@435:   return cur_as_bytes[offset];
duke@435: }
coleenp@548: 
coleenp@548: unsigned Atomic::xchg(unsigned int exchange_value, volatile unsigned int* dest) {
coleenp@548:   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
coleenp@548:   return (unsigned int)Atomic::xchg((jint)exchange_value, (volatile jint*)dest);
coleenp@548: }
coleenp@548: 
coleenp@548: unsigned Atomic::cmpxchg(unsigned int exchange_value,
coleenp@548:                          volatile unsigned int* dest, unsigned int compare_value) {
coleenp@548:   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
coleenp@548:   return (unsigned int)Atomic::cmpxchg((jint)exchange_value, (volatile jint*)dest,
coleenp@548:                                        (jint)compare_value);
coleenp@548: }
minqi@2964: 
minqi@2964: jlong Atomic::add(jlong    add_value, volatile jlong*    dest) {
minqi@2964:   jlong old = load(dest);
minqi@2964:   jlong new_value = old + add_value;
minqi@2964:   while (old != cmpxchg(new_value, dest, old)) {
minqi@2964:     old = load(dest);
minqi@2964:     new_value = old + add_value;
minqi@2964:   }
minqi@2964:   return old;
minqi@2964: }
iklam@5306: 
iklam@5306: void Atomic::inc(volatile short* dest) {
iklam@5306:   // Most platforms do not support atomic increment on a 2-byte value. However,
iklam@5306:   // if the value occupies the most significant 16 bits of an aligned 32-bit
iklam@5306:   // word, then we can do this with an atomic add of 0x10000 to the 32-bit word.
iklam@5306:   //
iklam@5306:   // The least significant parts of this 32-bit word will never be affected, even
iklam@5306:   // in case of overflow/underflow.
iklam@5306:   //
iklam@5306:   // Use the ATOMIC_SHORT_PAIR macro to get the desired alignment.
iklam@5306: #ifdef VM_LITTLE_ENDIAN
iklam@5306:   assert((intx(dest) & 0x03) == 0x02, "wrong alignment");
iklam@5306:   (void)Atomic::add(0x10000, (volatile int*)(dest-1));
iklam@5306: #else
iklam@5306:   assert((intx(dest) & 0x03) == 0x00, "wrong alignment");
iklam@5306:   (void)Atomic::add(0x10000, (volatile int*)(dest));
iklam@5306: #endif
iklam@5306: }
iklam@5306: 
iklam@5306: void Atomic::dec(volatile short* dest) {
iklam@5306: #ifdef VM_LITTLE_ENDIAN
iklam@5306:   assert((intx(dest) & 0x03) == 0x02, "wrong alignment");
iklam@5306:   (void)Atomic::add(-0x10000, (volatile int*)(dest-1));
iklam@5306: #else
iklam@5306:   assert((intx(dest) & 0x03) == 0x00, "wrong alignment");
iklam@5306:   (void)Atomic::add(-0x10000, (volatile int*)(dest));
iklam@5306: #endif
iklam@5306: }
iklam@5306: