1 /*
   2  * Copyright (c) 2001, 2010, 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 "precompiled.hpp"
  26 #include "runtime/atomic.hpp"
  27 #ifdef TARGET_OS_FAMILY_linux
  28 # include "os_linux.inline.hpp"
  29 #endif
  30 #ifdef TARGET_OS_FAMILY_solaris
  31 # include "os_solaris.inline.hpp"
  32 #endif
  33 #ifdef TARGET_OS_FAMILY_windows
  34 # include "os_windows.inline.hpp"
  35 #endif
  36 #ifdef TARGET_OS_ARCH_linux_x86
  37 # include "atomic_linux_x86.inline.hpp"
  38 #endif
  39 #ifdef TARGET_OS_ARCH_linux_sparc
  40 # include "atomic_linux_sparc.inline.hpp"
  41 #endif
  42 #ifdef TARGET_OS_ARCH_linux_zero
  43 # include "atomic_linux_zero.inline.hpp"
  44 #endif
  45 #ifdef TARGET_OS_ARCH_solaris_x86
  46 # include "atomic_solaris_x86.inline.hpp"
  47 #endif
  48 #ifdef TARGET_OS_ARCH_solaris_sparc
  49 # include "atomic_solaris_sparc.inline.hpp"
  50 #endif
  51 #ifdef TARGET_OS_ARCH_windows_x86
  52 # include "atomic_windows_x86.inline.hpp"
  53 #endif
  54 
  55 jbyte Atomic::cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) {
  56   assert(sizeof(jbyte) == 1, "assumption.");
  57   uintptr_t dest_addr = (uintptr_t)dest;
  58   uintptr_t offset = dest_addr % sizeof(jint);
  59   volatile jint* dest_int = (volatile jint*)(dest_addr - offset);
  60   jint cur = *dest_int;
  61   jbyte* cur_as_bytes = (jbyte*)(&cur);
  62   jint new_val = cur;
  63   jbyte* new_val_as_bytes = (jbyte*)(&new_val);
  64   new_val_as_bytes[offset] = exchange_value;
  65   while (cur_as_bytes[offset] == compare_value) {
  66     jint res = cmpxchg(new_val, dest_int, cur);
  67     if (res == cur) break;
  68     cur = res;
  69     new_val = cur;
  70     new_val_as_bytes[offset] = exchange_value;
  71   }
  72   return cur_as_bytes[offset];
  73 }
  74 
  75 unsigned Atomic::xchg(unsigned int exchange_value, volatile unsigned int* dest) {
  76   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
  77   return (unsigned int)Atomic::xchg((jint)exchange_value, (volatile jint*)dest);
  78 }
  79 
  80 unsigned Atomic::cmpxchg(unsigned int exchange_value,
  81                          volatile unsigned int* dest, unsigned int compare_value) {
  82   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
  83   return (unsigned int)Atomic::cmpxchg((jint)exchange_value, (volatile jint*)dest,
  84                                        (jint)compare_value);
  85 }