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src/share/vm/runtime/atomic.hpp

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rev 7584 : reusability maximum


   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 #ifndef SHARE_VM_RUNTIME_ATOMIC_HPP
  26 #define SHARE_VM_RUNTIME_ATOMIC_HPP
  27 
  28 #include "memory/allocation.hpp"

  29 
  30 class Atomic : AllStatic {
  31  private:


  32   static jbyte cmpxchg_general(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value);



























  33 

  34  public:
  35   // Atomic operations on jlong types are not available on all 32-bit
  36   // platforms. If atomic ops on jlongs are defined here they must only
  37   // be used from code that verifies they are available at runtime and
  38   // can provide an alternative action if not - see supports_cx8() for
  39   // a means to test availability.
  40 
  41   // The memory operations that are mentioned with each of the atomic
  42   // function families come from src/share/vm/runtime/orderAccess.hpp,
  43   // e.g., <fence> is described in that file and is implemented by the
  44   // OrderAccess::fence() function. See that file for the gory details
  45   // on the Memory Access Ordering Model.
  46 
  47   // All of the atomic operations that imply a read-modify-write action
  48   // guarantee a two-way memory barrier across that operation. Historically
  49   // these semantics reflect the strength of atomic operations that are
  50   // provided on SPARC/X86. We assume that strength is necessary unless
  51   // we can prove that a weaker form is sufficiently safe.
  52 
  53   // Atomically store to a location




   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 #ifndef SHARE_VM_RUNTIME_ATOMIC_HPP
  26 #define SHARE_VM_RUNTIME_ATOMIC_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "utilities/traits/selectBaseClass.hpp"
  30 
  31 class AtomicPlatform;
  32 
  33 class AtomicBase : AllStatic {
  34  protected:
  35   static jbyte cmpxchg_general(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value);
  36  public:
  37   inline static jbyte cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) {
  38     return cmpxchg_general(exchange_value, dest, compare_value);
  39   }
  40 };
  41 
  42 // Linux
  43 #ifdef TARGET_OS_ARCH_linux_x86
  44 # include "atomic_linux_x86.hpp"
  45 #endif
  46 
  47 // Solaris
  48 #ifdef TARGET_OS_ARCH_solaris_x86
  49 # include "atomic_solaris_x86.hpp"
  50 #endif
  51 
  52 // Windows
  53 #ifdef TARGET_OS_ARCH_windows_x86
  54 # include "atomic_windows_x86.hpp"
  55 #endif
  56 
  57 // BSD
  58 #ifdef TARGET_OS_ARCH_bsd_x86
  59 # include "atomic_bsd_x86.hpp"
  60 #endif
  61 
  62 typedef SelectBaseClass<AtomicPlatform, AtomicBase>::type AtomicSuper;
  63 
  64 class Atomic : public AtomicSuper {
  65  public:
  66   // Atomic operations on jlong types are not available on all 32-bit
  67   // platforms. If atomic ops on jlongs are defined here they must only
  68   // be used from code that verifies they are available at runtime and
  69   // can provide an alternative action if not - see supports_cx8() for
  70   // a means to test availability.
  71 
  72   // The memory operations that are mentioned with each of the atomic
  73   // function families come from src/share/vm/runtime/orderAccess.hpp,
  74   // e.g., <fence> is described in that file and is implemented by the
  75   // OrderAccess::fence() function. See that file for the gory details
  76   // on the Memory Access Ordering Model.
  77 
  78   // All of the atomic operations that imply a read-modify-write action
  79   // guarantee a two-way memory barrier across that operation. Historically
  80   // these semantics reflect the strength of atomic operations that are
  81   // provided on SPARC/X86. We assume that strength is necessary unless
  82   // we can prove that a weaker form is sufficiently safe.
  83 
  84   // Atomically store to a location


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