--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/runtime/atomic.hpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,602 @@
+/*
+ * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_RUNTIME_ATOMIC_HPP
+#define SHARE_VM_RUNTIME_ATOMIC_HPP
+
+#include "memory/allocation.hpp"
+#include "metaprogramming/conditional.hpp"
+#include "metaprogramming/enableIf.hpp"
+#include "metaprogramming/isIntegral.hpp"
+#include "metaprogramming/isPointer.hpp"
+#include "metaprogramming/isSame.hpp"
+#include "metaprogramming/primitiveConversions.hpp"
+#include "metaprogramming/removeCV.hpp"
+#include "metaprogramming/removePointer.hpp"
+#include "utilities/align.hpp"
+#include "utilities/macros.hpp"
+
+enum cmpxchg_memory_order {
+ memory_order_relaxed,
+ // Use value which doesn't interfere with C++2011. We need to be more conservative.
+ memory_order_conservative = 8
+};
+
+class Atomic : AllStatic {
+ public:
+ // Atomic operations on jlong types are not available on all 32-bit
+ // platforms. If atomic ops on jlongs are defined here they must only
+ // be used from code that verifies they are available at runtime and
+ // can provide an alternative action if not - see supports_cx8() for
+ // a means to test availability.
+
+ // The memory operations that are mentioned with each of the atomic
+ // function families come from src/share/vm/runtime/orderAccess.hpp,
+ // e.g., <fence> is described in that file and is implemented by the
+ // OrderAccess::fence() function. See that file for the gory details
+ // on the Memory Access Ordering Model.
+
+ // All of the atomic operations that imply a read-modify-write action
+ // guarantee a two-way memory barrier across that operation. Historically
+ // these semantics reflect the strength of atomic operations that are
+ // provided on SPARC/X86. We assume that strength is necessary unless
+ // we can prove that a weaker form is sufficiently safe.
+
+ // Atomically store to a location
+ inline static void store (jbyte store_value, jbyte* dest);
+ inline static void store (jshort store_value, jshort* dest);
+ inline static void store (jint store_value, jint* dest);
+ // See comment above about using jlong atomics on 32-bit platforms
+ inline static void store (jlong store_value, jlong* dest);
+ inline static void store_ptr(intptr_t store_value, intptr_t* dest);
+ inline static void store_ptr(void* store_value, void* dest);
+
+ inline static void store (jbyte store_value, volatile jbyte* dest);
+ inline static void store (jshort store_value, volatile jshort* dest);
+ inline static void store (jint store_value, volatile jint* dest);
+ // See comment above about using jlong atomics on 32-bit platforms
+ inline static void store (jlong store_value, volatile jlong* dest);
+ inline static void store_ptr(intptr_t store_value, volatile intptr_t* dest);
+ inline static void store_ptr(void* store_value, volatile void* dest);
+
+ // See comment above about using jlong atomics on 32-bit platforms
+ inline static jlong load(const volatile jlong* src);
+
+ // Atomically add to a location. Returns updated value. add*() provide:
+ // <fence> add-value-to-dest <membar StoreLoad|StoreStore>
+
+ template<typename I, typename D>
+ inline static D add(I add_value, D volatile* dest);
+
+ inline static intptr_t add_ptr(intptr_t add_value, volatile intptr_t* dest) {
+ return add(add_value, dest);
+ }
+
+ inline static void* add_ptr(intptr_t add_value, volatile void* dest) {
+ return add(add_value, reinterpret_cast<char* volatile*>(dest));
+ }
+
+ // Atomically increment location. inc*() provide:
+ // <fence> increment-dest <membar StoreLoad|StoreStore>
+ inline static void inc (volatile jint* dest);
+ inline static void inc (volatile jshort* dest);
+ inline static void inc (volatile size_t* dest);
+ inline static void inc_ptr(volatile intptr_t* dest);
+ inline static void inc_ptr(volatile void* dest);
+
+ // Atomically decrement a location. dec*() provide:
+ // <fence> decrement-dest <membar StoreLoad|StoreStore>
+ inline static void dec (volatile jint* dest);
+ inline static void dec (volatile jshort* dest);
+ inline static void dec (volatile size_t* dest);
+ inline static void dec_ptr(volatile intptr_t* dest);
+ inline static void dec_ptr(volatile void* dest);
+
+ // Performs atomic exchange of *dest with exchange_value. Returns old
+ // prior value of *dest. xchg*() provide:
+ // <fence> exchange-value-with-dest <membar StoreLoad|StoreStore>
+ inline static jint xchg (jint exchange_value, volatile jint* dest);
+ inline static unsigned int xchg (unsigned int exchange_value, volatile unsigned int* dest);
+ inline static intptr_t xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest);
+ inline static void* xchg_ptr(void* exchange_value, volatile void* dest);
+
+ // Performs atomic compare of *dest and compare_value, and exchanges
+ // *dest with exchange_value if the comparison succeeded. Returns prior
+ // value of *dest. cmpxchg*() provide:
+ // <fence> compare-and-exchange <membar StoreLoad|StoreStore>
+
+ template<typename T, typename D, typename U>
+ inline static D cmpxchg(T exchange_value,
+ D volatile* dest,
+ U compare_value,
+ cmpxchg_memory_order order = memory_order_conservative);
+
+ // Performs atomic compare of *dest and NULL, and replaces *dest
+ // with exchange_value if the comparison succeeded. Returns true if
+ // the comparison succeeded and the exchange occurred. This is
+ // often used as part of lazy initialization, as a lock-free
+ // alternative to the Double-Checked Locking Pattern.
+ template<typename T, typename D>
+ inline static bool replace_if_null(T* value, D* volatile* dest,
+ cmpxchg_memory_order order = memory_order_conservative);
+
+ inline static intptr_t cmpxchg_ptr(intptr_t exchange_value,
+ volatile intptr_t* dest,
+ intptr_t compare_value,
+ cmpxchg_memory_order order = memory_order_conservative) {
+ return cmpxchg(exchange_value, dest, compare_value, order);
+ }
+
+ inline static void* cmpxchg_ptr(void* exchange_value,
+ volatile void* dest,
+ void* compare_value,
+ cmpxchg_memory_order order = memory_order_conservative) {
+ return cmpxchg(exchange_value,
+ reinterpret_cast<void* volatile*>(dest),
+ compare_value,
+ order);
+ }
+
+private:
+ // Test whether From is implicitly convertible to To.
+ // From and To must be pointer types.
+ // Note: Provides the limited subset of C++11 std::is_convertible
+ // that is needed here.
+ template<typename From, typename To> struct IsPointerConvertible;
+
+ // Dispatch handler for add. Provides type-based validity checking
+ // and limited conversions around calls to the platform-specific
+ // implementation layer provided by PlatformAdd.
+ template<typename I, typename D, typename Enable = void>
+ struct AddImpl;
+
+ // Platform-specific implementation of add. Support for sizes of 4
+ // bytes and (if different) pointer size bytes are required. The
+ // class is a function object that must be default constructable,
+ // with these requirements:
+ //
+ // - dest is of type D*, an integral or pointer type.
+ // - add_value is of type I, an integral type.
+ // - sizeof(I) == sizeof(D).
+ // - if D is an integral type, I == D.
+ // - platform_add is an object of type PlatformAdd<sizeof(D)>.
+ //
+ // Then
+ // platform_add(add_value, dest)
+ // must be a valid expression, returning a result convertible to D.
+ //
+ // No definition is provided; all platforms must explicitly define
+ // this class and any needed specializations.
+ template<size_t byte_size> struct PlatformAdd;
+
+ // Helper base classes for defining PlatformAdd. To use, define
+ // PlatformAdd or a specialization that derives from one of these,
+ // and include in the PlatformAdd definition the support function
+ // (described below) required by the base class.
+ //
+ // These classes implement the required function object protocol for
+ // PlatformAdd, using a support function template provided by the
+ // derived class. Let add_value (of type I) and dest (of type D) be
+ // the arguments the object is called with. If D is a pointer type
+ // P*, then let addend (of type I) be add_value * sizeof(P);
+ // otherwise, addend is add_value.
+ //
+ // FetchAndAdd requires the derived class to provide
+ // fetch_and_add(addend, dest)
+ // atomically adding addend to the value of dest, and returning the
+ // old value.
+ //
+ // AddAndFetch requires the derived class to provide
+ // add_and_fetch(addend, dest)
+ // atomically adding addend to the value of dest, and returning the
+ // new value.
+ //
+ // When D is a pointer type P*, both fetch_and_add and add_and_fetch
+ // treat it as if it were a uintptr_t; they do not perform any
+ // scaling of the addend, as that has already been done by the
+ // caller.
+public: // Temporary, can't be private: C++03 11.4/2. Fixed by C++11.
+ template<typename Derived> struct FetchAndAdd;
+ template<typename Derived> struct AddAndFetch;
+private:
+
+ // Support for platforms that implement some variants of add using a
+ // (typically out of line) non-template helper function. The
+ // generic arguments passed to PlatformAdd need to be translated to
+ // the appropriate type for the helper function, the helper function
+ // invoked on the translated arguments, and the result translated
+ // back. Type is the parameter / return type of the helper
+ // function. No scaling of add_value is performed when D is a pointer
+ // type, so this function can be used to implement the support function
+ // required by AddAndFetch.
+ template<typename Type, typename Fn, typename I, typename D>
+ static D add_using_helper(Fn fn, I add_value, D volatile* dest);
+
+ // Dispatch handler for cmpxchg. Provides type-based validity
+ // checking and limited conversions around calls to the
+ // platform-specific implementation layer provided by
+ // PlatformCmpxchg.
+ template<typename T, typename D, typename U, typename Enable = void>
+ struct CmpxchgImpl;
+
+ // Platform-specific implementation of cmpxchg. Support for sizes
+ // of 1, 4, and 8 are required. The class is a function object that
+ // must be default constructable, with these requirements:
+ //
+ // - dest is of type T*.
+ // - exchange_value and compare_value are of type T.
+ // - order is of type cmpxchg_memory_order.
+ // - platform_cmpxchg is an object of type PlatformCmpxchg<sizeof(T)>.
+ //
+ // Then
+ // platform_cmpxchg(exchange_value, dest, compare_value, order)
+ // must be a valid expression, returning a result convertible to T.
+ //
+ // A default definition is provided, which declares a function template
+ // T operator()(T, T volatile*, T, cmpxchg_memory_order) const
+ //
+ // For each required size, a platform must either provide an
+ // appropriate definition of that function, or must entirely
+ // specialize the class template for that size.
+ template<size_t byte_size> struct PlatformCmpxchg;
+
+ // Support for platforms that implement some variants of cmpxchg
+ // using a (typically out of line) non-template helper function.
+ // The generic arguments passed to PlatformCmpxchg need to be
+ // translated to the appropriate type for the helper function, the
+ // helper invoked on the translated arguments, and the result
+ // translated back. Type is the parameter / return type of the
+ // helper function.
+ template<typename Type, typename Fn, typename T>
+ static T cmpxchg_using_helper(Fn fn,
+ T exchange_value,
+ T volatile* dest,
+ T compare_value);
+
+ // Support platforms that do not provide Read-Modify-Write
+ // byte-level atomic access. To use, derive PlatformCmpxchg<1> from
+ // this class.
+public: // Temporary, can't be private: C++03 11.4/2. Fixed by C++11.
+ struct CmpxchgByteUsingInt;
+private:
+};
+
+template<typename From, typename To>
+struct Atomic::IsPointerConvertible<From*, To*> : AllStatic {
+ // Determine whether From* is implicitly convertible to To*, using
+ // the "sizeof trick".
+ typedef char yes;
+ typedef char (&no)[2];
+
+ static yes test(To*);
+ static no test(...);
+ static From* test_value;
+
+ static const bool value = (sizeof(yes) == sizeof(test(test_value)));
+};
+
+// Define FetchAndAdd and AddAndFetch helper classes before including
+// platform file, which may use these as base classes, requiring they
+// be complete.
+
+template<typename Derived>
+struct Atomic::FetchAndAdd VALUE_OBJ_CLASS_SPEC {
+ template<typename I, typename D>
+ D operator()(I add_value, D volatile* dest) const;
+};
+
+template<typename Derived>
+struct Atomic::AddAndFetch VALUE_OBJ_CLASS_SPEC {
+ template<typename I, typename D>
+ D operator()(I add_value, D volatile* dest) const;
+};
+
+// Define the class before including platform file, which may specialize
+// the operator definition. No generic definition of specializations
+// of the operator template are provided, nor are there any generic
+// specializations of the class. The platform file is responsible for
+// providing those.
+template<size_t byte_size>
+struct Atomic::PlatformCmpxchg VALUE_OBJ_CLASS_SPEC {
+ template<typename T>
+ T operator()(T exchange_value,
+ T volatile* dest,
+ T compare_value,
+ cmpxchg_memory_order order) const;
+};
+
+// Define the class before including platform file, which may use this
+// as a base class, requiring it be complete. The definition is later
+// in this file, near the other definitions related to cmpxchg.
+struct Atomic::CmpxchgByteUsingInt VALUE_OBJ_CLASS_SPEC {
+ template<typename T>
+ T operator()(T exchange_value,
+ T volatile* dest,
+ T compare_value,
+ cmpxchg_memory_order order) const;
+};
+
+// platform specific in-line definitions - must come before shared definitions
+
+#include OS_CPU_HEADER(atomic)
+
+// shared in-line definitions
+
+// size_t casts...
+#if (SIZE_MAX != UINTPTR_MAX)
+#error size_t is not WORD_SIZE, interesting platform, but missing implementation here
+#endif
+
+template<typename I, typename D>
+inline D Atomic::add(I add_value, D volatile* dest) {
+ return AddImpl<I, D>()(add_value, dest);
+}
+
+template<typename I, typename D>
+struct Atomic::AddImpl<
+ I, D,
+ typename EnableIf<IsIntegral<I>::value &&
+ IsIntegral<D>::value &&
+ (sizeof(I) <= sizeof(D)) &&
+ (IsSigned<I>::value == IsSigned<D>::value)>::type>
+ VALUE_OBJ_CLASS_SPEC
+{
+ D operator()(I add_value, D volatile* dest) const {
+ D addend = add_value;
+ return PlatformAdd<sizeof(D)>()(addend, dest);
+ }
+};
+
+template<typename I, typename P>
+struct Atomic::AddImpl<
+ I, P*,
+ typename EnableIf<IsIntegral<I>::value && (sizeof(I) <= sizeof(P*))>::type>
+ VALUE_OBJ_CLASS_SPEC
+{
+ P* operator()(I add_value, P* volatile* dest) const {
+ STATIC_ASSERT(sizeof(intptr_t) == sizeof(P*));
+ STATIC_ASSERT(sizeof(uintptr_t) == sizeof(P*));
+ typedef typename Conditional<IsSigned<I>::value,
+ intptr_t,
+ uintptr_t>::type CI;
+ CI addend = add_value;
+ return PlatformAdd<sizeof(P*)>()(addend, dest);
+ }
+};
+
+// Most platforms do not support atomic add on a 2-byte value. However,
+// if the value occupies the most significant 16 bits of an aligned 32-bit
+// word, then we can do this with an atomic add of (add_value << 16)
+// to the 32-bit word.
+//
+// The least significant parts of this 32-bit word will never be affected, even
+// in case of overflow/underflow.
+//
+// Use the ATOMIC_SHORT_PAIR macro (see macros.hpp) to get the desired alignment.
+template<>
+struct Atomic::AddImpl<jshort, jshort> VALUE_OBJ_CLASS_SPEC {
+ jshort operator()(jshort add_value, jshort volatile* dest) const {
+#ifdef VM_LITTLE_ENDIAN
+ assert((intx(dest) & 0x03) == 0x02, "wrong alignment");
+ jint new_value = Atomic::add(add_value << 16, (volatile jint*)(dest-1));
+#else
+ assert((intx(dest) & 0x03) == 0x00, "wrong alignment");
+ jint new_value = Atomic::add(add_value << 16, (volatile jint*)(dest));
+#endif
+ return (jshort)(new_value >> 16); // preserves sign
+ }
+};
+
+template<typename Derived>
+template<typename I, typename D>
+inline D Atomic::FetchAndAdd<Derived>::operator()(I add_value, D volatile* dest) const {
+ I addend = add_value;
+ // If D is a pointer type P*, scale by sizeof(P).
+ if (IsPointer<D>::value) {
+ addend *= sizeof(typename RemovePointer<D>::type);
+ }
+ D old = static_cast<const Derived*>(this)->fetch_and_add(addend, dest);
+ return old + add_value;
+}
+
+template<typename Derived>
+template<typename I, typename D>
+inline D Atomic::AddAndFetch<Derived>::operator()(I add_value, D volatile* dest) const {
+ // If D is a pointer type P*, scale by sizeof(P).
+ if (IsPointer<D>::value) {
+ add_value *= sizeof(typename RemovePointer<D>::type);
+ }
+ return static_cast<const Derived*>(this)->add_and_fetch(add_value, dest);
+}
+
+template<typename Type, typename Fn, typename I, typename D>
+inline D Atomic::add_using_helper(Fn fn, I add_value, D volatile* dest) {
+ return PrimitiveConversions::cast<D>(
+ fn(PrimitiveConversions::cast<Type>(add_value),
+ reinterpret_cast<Type volatile*>(dest)));
+}
+
+inline void Atomic::inc(volatile size_t* dest) {
+ inc_ptr((volatile intptr_t*) dest);
+}
+
+inline void Atomic::dec(volatile size_t* dest) {
+ dec_ptr((volatile intptr_t*) dest);
+}
+
+template<typename T, typename D, typename U>
+inline D Atomic::cmpxchg(T exchange_value,
+ D volatile* dest,
+ U compare_value,
+ cmpxchg_memory_order order) {
+ return CmpxchgImpl<T, D, U>()(exchange_value, dest, compare_value, order);
+}
+
+template<typename T, typename D>
+inline bool Atomic::replace_if_null(T* value, D* volatile* dest,
+ cmpxchg_memory_order order) {
+ // Presently using a trivial implementation in terms of cmpxchg.
+ // Consider adding platform support, to permit the use of compiler
+ // intrinsics like gcc's __sync_bool_compare_and_swap.
+ D* expected_null = NULL;
+ return expected_null == cmpxchg(value, dest, expected_null, order);
+}
+
+// Handle cmpxchg for integral and enum types.
+//
+// All the involved types must be identical.
+template<typename T>
+struct Atomic::CmpxchgImpl<
+ T, T, T,
+ typename EnableIf<IsIntegral<T>::value || IsRegisteredEnum<T>::value>::type>
+ VALUE_OBJ_CLASS_SPEC
+{
+ T operator()(T exchange_value, T volatile* dest, T compare_value,
+ cmpxchg_memory_order order) const {
+ // Forward to the platform handler for the size of T.
+ return PlatformCmpxchg<sizeof(T)>()(exchange_value,
+ dest,
+ compare_value,
+ order);
+ }
+};
+
+// Handle cmpxchg for pointer types.
+//
+// The destination's type and the compare_value type must be the same,
+// ignoring cv-qualifiers; we don't care about the cv-qualifiers of
+// the compare_value.
+//
+// The exchange_value must be implicitly convertible to the
+// destination's type; it must be type-correct to store the
+// exchange_value in the destination.
+template<typename T, typename D, typename U>
+struct Atomic::CmpxchgImpl<
+ T*, D*, U*,
+ typename EnableIf<Atomic::IsPointerConvertible<T*, D*>::value &&
+ IsSame<typename RemoveCV<D>::type,
+ typename RemoveCV<U>::type>::value>::type>
+ VALUE_OBJ_CLASS_SPEC
+{
+ D* operator()(T* exchange_value, D* volatile* dest, U* compare_value,
+ cmpxchg_memory_order order) const {
+ // Allow derived to base conversion, and adding cv-qualifiers.
+ D* new_value = exchange_value;
+ // Don't care what the CV qualifiers for compare_value are,
+ // but we need to match D* when calling platform support.
+ D* old_value = const_cast<D*>(compare_value);
+ return PlatformCmpxchg<sizeof(D*)>()(new_value, dest, old_value, order);
+ }
+};
+
+// Handle cmpxchg for types that have a translator.
+//
+// All the involved types must be identical.
+//
+// This translates the original call into a call on the decayed
+// arguments, and returns the recovered result of that translated
+// call.
+template<typename T>
+struct Atomic::CmpxchgImpl<
+ T, T, T,
+ typename EnableIf<PrimitiveConversions::Translate<T>::value>::type>
+ VALUE_OBJ_CLASS_SPEC
+{
+ T operator()(T exchange_value, T volatile* dest, T compare_value,
+ cmpxchg_memory_order order) const {
+ typedef PrimitiveConversions::Translate<T> Translator;
+ typedef typename Translator::Decayed Decayed;
+ STATIC_ASSERT(sizeof(T) == sizeof(Decayed));
+ return Translator::recover(
+ cmpxchg(Translator::decay(exchange_value),
+ reinterpret_cast<Decayed volatile*>(dest),
+ Translator::decay(compare_value),
+ order));
+ }
+};
+
+template<typename Type, typename Fn, typename T>
+inline T Atomic::cmpxchg_using_helper(Fn fn,
+ T exchange_value,
+ T volatile* dest,
+ T compare_value) {
+ STATIC_ASSERT(sizeof(Type) == sizeof(T));
+ return PrimitiveConversions::cast<T>(
+ fn(PrimitiveConversions::cast<Type>(exchange_value),
+ reinterpret_cast<Type volatile*>(dest),
+ PrimitiveConversions::cast<Type>(compare_value)));
+}
+
+template<typename T>
+inline T Atomic::CmpxchgByteUsingInt::operator()(T exchange_value,
+ T volatile* dest,
+ T compare_value,
+ cmpxchg_memory_order order) const {
+ STATIC_ASSERT(sizeof(T) == sizeof(uint8_t));
+ uint8_t canon_exchange_value = exchange_value;
+ uint8_t canon_compare_value = compare_value;
+ volatile uint32_t* aligned_dest
+ = reinterpret_cast<volatile uint32_t*>(align_down(dest, sizeof(uint32_t)));
+ size_t offset = pointer_delta(dest, aligned_dest, 1);
+ uint32_t cur = *aligned_dest;
+ uint8_t* cur_as_bytes = reinterpret_cast<uint8_t*>(&cur);
+
+ // current value may not be what we are looking for, so force it
+ // to that value so the initial cmpxchg will fail if it is different
+ cur_as_bytes[offset] = canon_compare_value;
+
+ // always execute a real cmpxchg so that we get the required memory
+ // barriers even on initial failure
+ do {
+ // value to swap in matches current value ...
+ uint32_t new_value = cur;
+ // ... except for the one jbyte we want to update
+ reinterpret_cast<uint8_t*>(&new_value)[offset] = canon_exchange_value;
+
+ uint32_t res = cmpxchg(new_value, aligned_dest, cur, order);
+ if (res == cur) break; // success
+
+ // at least one byte in the int changed value, so update
+ // our view of the current int
+ cur = res;
+ // if our byte is still as cur we loop and try again
+ } while (cur_as_bytes[offset] == canon_compare_value);
+
+ return PrimitiveConversions::cast<T>(cur_as_bytes[offset]);
+}
+
+inline unsigned Atomic::xchg(unsigned int exchange_value, volatile unsigned int* dest) {
+ assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
+ return (unsigned int)Atomic::xchg((jint)exchange_value, (volatile jint*)dest);
+}
+
+inline void Atomic::inc(volatile jshort* dest) {
+ (void)add(jshort(1), dest);
+}
+
+inline void Atomic::dec(volatile jshort* dest) {
+ (void)add(jshort(-1), dest);
+}
+
+#endif // SHARE_VM_RUNTIME_ATOMIC_HPP