diff --git a/mc8051fun.h b/mc8051fun.h
index d07da1d..d481c63 100644
--- a/mc8051fun.h
+++ b/mc8051fun.h
@@ -77,6 +77,14 @@ uint8_t getport(int n);
 
 
 
+#define AR0 0x00
+#define AR1 0x01
+#define AR2 0x02
+#define AR3 0x03
+#define AR4 0x04
+#define AR5 0x05
+#define AR6 0x06
+#define AR7 0x07