diff --git a/EdkCompatibilityPkg/Foundation/Include/EfiStdArg.h b/EdkCompatibilityPkg/Foundation/Include/EfiStdArg.h
index 5697371b8a..94b93ea4d1 100644
--- a/EdkCompatibilityPkg/Foundation/Include/EfiStdArg.h
+++ b/EdkCompatibilityPkg/Foundation/Include/EfiStdArg.h
@@ -137,7 +137,7 @@ typedef CHAR8 *VA_LIST;
   @return  A pointer to the beginning of a variable argument list.
 
 **/
-#define VA_START(Marker, Parameter) (Marker = (VA_LIST) & (Parameter) + _INT_SIZE_OF (Parameter))
+#define VA_START(Marker, Parameter) (Marker = (VA_LIST) ((UINTN) & (Parameter) + _INT_SIZE_OF (Parameter)))
 
 /**
   Returns an argument of a specified type from a variable argument list and updates