Add atomic_add for 64-bit integers.

Now only GCC intrinsics are used.

include/maxscale/atomic.h

@@ -21,11 +21,7 @@
 MXS_BEGIN_DECLS
 
 /**
- * Implementation of an atomic add operation for the GCC environment, or the
+ * Implementation of an atomic add operations for the GCC environment.
- * X86 processor.  If we are working within GNU C then we can use the GCC
- * atomic add built in function, which is portable across platforms that
- * implement GCC.  Otherwise, this function currently supports only X86
- * architecture (without further development).
  *
  * Adds a value to the contents of a location pointed to by the first parameter.
  * The add operation is atomic and the return value is the value stored in the
@@ -36,7 +32,9 @@ MXS_BEGIN_DECLS
  * @param value         Value to be added
  * @return              The value of variable before the add occurred
  */
-int atomic_add(int *variable, int value);
+int      atomic_add(int *variable, int value);
+int64_t  atomic_add_int64(int64_t *variable, int64_t value);
+uint64_t atomic_add_uint64(uint64_t *variable, int64_t value);
 
 /**
  * @brief Impose a full memory barrier

server/core/atomic.c

@@ -11,29 +11,23 @@
  * Public License.
  */
 
+#include <maxscale/atomic.h>
+
 /**
  * @file atomic.c  - Implementation of atomic operations for MaxScale
- *
- * @verbatim
- * Revision History
- *
- * Date         Who             Description
- * 10/06/13     Mark Riddoch    Initial implementation
- *
- * @endverbatim
  */
 
-int
+int atomic_add(int *variable, int value)
-atomic_add(int *variable, int value)
 {
-#ifdef __GNUC__
+    return __sync_fetch_and_add(variable, value);
-    return (int) __sync_fetch_and_add (variable, value);
+}
-#else
+
-    asm volatile(
+int64_t atomic_add_int64(int64_t *variable, int64_t value)
-        "lock; xaddl %%eax, %2;"
+{
-        :"=a" (value)
+    return __sync_fetch_and_add(variable, value);
-        : "a" (value), "m" (*variable)
+}
-        : "memory" );
+
-    return value;
+uint64_t atomic_add_uint64(uint64_t *variable, int64_t value)
-#endif
+{
+    return __sync_fetch_and_add(variable, value);
 }