diff --git a/Processors/65816/65816.hpp b/Processors/65816/65816.hpp
index f47d9711b..3843520c0 100644
--- a/Processors/65816/65816.hpp
+++ b/Processors/65816/65816.hpp
@@ -9,6 +9,7 @@
 #ifndef WDC65816_hpp
 #define WDC65816_hpp
 
+#include <cassert>	// TEMPORARILY.
 #include <cstdint>
 #include <vector>