diff --git a/snes/smp/core/registers.hpp b/snes/smp/core/registers.hpp
index b033c42..3da86c0 100644
--- a/snes/smp/core/registers.hpp
+++ b/snes/smp/core/registers.hpp
@@ -12,9 +12,9 @@ struct flag_t {
     return data;
   }
 
-  inline unsigned operator|=(uint8 data) { return operator=(operator unsigned() | data); }
-  inline unsigned operator^=(uint8 data) { return operator=(operator unsigned() ^ data); }
-  inline unsigned operator&=(uint8 data) { return operator=(operator unsigned() & data); }
+  inline unsigned operator|=(uint8 data) { return (*this)=(operator unsigned() | data); }
+  inline unsigned operator^=(uint8 data) { return (*this)=(operator unsigned() ^ data); }
+  inline unsigned operator&=(uint8 data) { return (*this)=(operator unsigned() & data); }
 };
 
 struct word_t {