diff --git a/test/ref/Makefile b/test/ref/Makefile
index c986513b8..3c2e582e4 100644
--- a/test/ref/Makefile
+++ b/test/ref/Makefile
@@ -33,7 +33,7 @@ SIM65 := $(if $(wildcard ../../bin/sim65*),..$S..$Sbin$Ssim65,sim65)
 
 WORKDIR = ..$S..$Stestwrk$Sref
 
-OPTIONS = g O Os Osi Osir Oi Oir Or
+OPTIONS = g O Os Osi Osir Osr Oi Oir Or
 
 DIFF = $(WORKDIR)$Sbdiff$(EXE)