1 files changed, 37 insertions, 0 deletions
diff --git a/atomic.h b/atomic.h
new file mode 100644
index 0000000000..dd62b0c9fd
--- /dev/null
+++ b/atomic.h
@@ -0,0 +1,37 @@
+#ifndef RUBY_ATOMIC_H
+#define RUBY_ATOMIC_H
+
+#ifdef _WIN32
+#pragma intrinsic(_InterlockedOr)
+typedef LONG rb_atomic_t;
+
+# define ATOMIC_SET(var, val) InterlockedExchange(&(var), (val))
+# define ATOMIC_INC(var) InterlockedIncrement(&(var))
+# define ATOMIC_DEC(var) InterlockedDecrement(&(var))
+# define ATOMIC_OR(var, val) _InterlockedOr(&(var), (val))
+# define ATOMIC_EXCHANGE(var, val) InterlockedExchange(&(var), (val))
+
+#elif defined HAVE_GCC_ATOMIC_BUILTINS
+/* @shyouhei hack to support atomic operations in case of gcc. Gcc
+ * has its own pseudo-insns to support them.  See info, or
+ * http://gcc.gnu.org/onlinedocs/gcc/Atomic-Builtins.html */
+
+typedef unsigned int rb_atomic_t; /* Anything OK */
+# define ATOMIC_SET(var, val)  __sync_lock_test_and_set(&(var), (val))
+# define ATOMIC_INC(var) __sync_fetch_and_add(&(var), 1)
+# define ATOMIC_DEC(var) __sync_fetch_and_sub(&(var), 1)
+# define ATOMIC_OR(var, val) __sync_or_and_fetch(&(var), (val))
+# define ATOMIC_EXCHANGE(var, val) __sync_lock_test_and_set(&(var), (val))
+
+#else
+typedef int rb_atomic_t;
+extern rb_atomic_t ruby_atomic_exchange(rb_atomic_t *ptr, rb_atomic_t val);
+
+# define ATOMIC_SET(var, val) ((var) = (val))
+# define ATOMIC_INC(var) (++(var))
+# define ATOMIC_DEC(var) (--(var))
+# define ATOMIC_OR(var, val) ((var) |= (val))
+# define ATOMIC_EXCHANGE(var, val) ruby_atomic_exchange(&(var), (val))
+#endif
+
+#endif /* RUBY_ATOMIC_H */