diff --git a/target-i386/ops_template.h b/target-i386/ops_template.h
index 044968a2ca..35d5b54121 100644
--- a/target-i386/ops_template.h
+++ b/target-i386/ops_template.h
@@ -46,7 +46,7 @@
 #define SUFFIX q
 #define DATA_TYPE uint64_t
 #define DATA_STYPE int64_t
-#define DATA_MASK 0xffffffffffffffff
+#define DATA_MASK 0xffffffffffffffffULL
 #else
 #error unhandled operand size
 #endif