+ /* This 'useless' struct is declared just so we can use partial template
+ * specialization in our store and load functions. */
+ template <typename T, size_t n>
+ struct useless {
+ static void store(void *addr, T val);
+ static T load(const void *addr);
+ };
+
+ template <typename T>
+ struct useless<T, 1> {
+ static void store(void *addr, T val) { store_8(addr, (uint8_t)val); }
+ static T load(const void *addr) { return (T)load_8(addr); }
+ };
+
+ template <typename T>
+ struct useless<T, 2> {
+ static void store(void *addr, T val) { store_16(addr, (uint16_t)val); }
+ static T load(const void *addr) { return (T)load_16(addr); }
+ };
+
+ template <typename T>
+ struct useless<T, 4> {
+ static void store(void *addr, T val) { store_32(addr, (uint32_t)val); }
+ static T load(const void *addr) { return (T)load_32(addr); }
+ };
+
+ template <typename T>
+ struct useless<T, 8> {
+ static void store(void *addr, T val) { store_64(addr, (uint64_t)val); }
+ static T load(const void *addr) { return (T)load_64(addr); }
+ };
+
+ template <typename T>
+ struct var {
+ var() { useless<T, sizeof(T)>::store(&value, 0); }
+ var(T v) { useless<T, sizeof(T)>::store(&value, v); }
+ var(var const& r) {
+ value = r.value;
+ }
+ ~var() { }
+
+ void operator = (T v) { useless<T, sizeof(T)>::store(&value, v); }
+ T operator () () { return useless<T, sizeof(T)>::load(&value); }
+ void operator += (T v) {
+ useless<T, sizeof(T)>::store(&value,
+ useless<T, sizeof(T)>::load(&value) + v);
+ }
+ bool operator == (const struct var<T> v) const { return useless<T, sizeof(T)>::load(&value) == useless<T, sizeof(T)>::load(&v.value); }
+
+ T value;
+ };
+