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.inline.hpp"
  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 }
  59 
  60 jlong Atomic::add(jlong    add_value, volatile jlong*    dest) {
  61   jlong old = load(dest);
  62   jlong new_value = old + add_value;
  63   while (old != cmpxchg(new_value, dest, old)) {
  64     old = load(dest);
  65     new_value = old + add_value;
  66   }

   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.inline.hpp"
  27 
  28 #ifndef X86
  29 jbyte Atomic::cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) {
  30   assert(sizeof(jbyte) == 1, "assumption.");
  31   uintptr_t dest_addr = (uintptr_t)dest;
  32   uintptr_t offset = dest_addr % sizeof(jint);
  33   volatile jint* dest_int = (volatile jint*)(dest_addr - offset);
  34   jint cur = *dest_int;
  35   jbyte* cur_as_bytes = (jbyte*)(&cur);
  36   jint new_val = cur;
  37   jbyte* new_val_as_bytes = (jbyte*)(&new_val);
  38   new_val_as_bytes[offset] = exchange_value;
  39   while (cur_as_bytes[offset] == compare_value) {
  40     jint res = cmpxchg(new_val, dest_int, cur);
  41     if (res == cur) break;
  42     cur = res;
  43     new_val = cur;
  44     new_val_as_bytes[offset] = exchange_value;
  45   }
  46   return cur_as_bytes[offset];
  47 }
  48 #endif
  49 
  50 unsigned Atomic::xchg(unsigned int exchange_value, volatile unsigned int* dest) {
  51   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
  52   return (unsigned int)Atomic::xchg((jint)exchange_value, (volatile jint*)dest);
  53 }
  54 
  55 unsigned Atomic::cmpxchg(unsigned int exchange_value,
  56                          volatile unsigned int* dest, unsigned int compare_value) {
  57   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
  58   return (unsigned int)Atomic::cmpxchg((jint)exchange_value, (volatile jint*)dest,
  59                                        (jint)compare_value);
  60 }
  61 
  62 jlong Atomic::add(jlong    add_value, volatile jlong*    dest) {
  63   jlong old = load(dest);
  64   jlong new_value = old + add_value;
  65   while (old != cmpxchg(new_value, dest, old)) {
  66     old = load(dest);
  67     new_value = old + add_value;
  68   }