diff --git a/src/mame/drivers/tomcat.c b/src/mame/drivers/tomcat.c
index 037386393c7..23954ce7f5a 100644
--- a/src/mame/drivers/tomcat.c
+++ b/src/mame/drivers/tomcat.c
@@ -197,6 +197,7 @@ static READ16_HANDLER(dsp_BIO_r)
 		else
 		{
 			assert(0);
+			return 0;
 		}
 	}
 	else