diff --git a/gen-driver.S b/gen-driver.S
index d645917..fca3390 100644
--- a/gen-driver.S
+++ b/gen-driver.S
@@ -10,6 +10,7 @@
 #define PORT_LATI0_BIT BIT2
 #define PORT_LATI1_BIT BIT3
 
+  .altmacro
 
   .macro set_data_bit
   bic         #PORT_SID_BIT, &PORT_REG
@@ -45,22 +46,11 @@ genShifter:
   //   R12 aka CHIP_ID_REGISTER: chip id, 0 or 1
   //   R13 aka DATA_REGISTER: frequency code, full 16 bit
 
-  data_cycle 0
-  data_cycle 1
-  data_cycle 2
-  data_cycle 3
-  data_cycle 4
-  data_cycle 5
-  data_cycle 6
-  data_cycle 7
-  data_cycle 8
-  data_cycle 9
-  data_cycle a
-  data_cycle b
-  data_cycle c
-  data_cycle d
-  data_cycle e
-  data_cycle f
+  .set counter, 0
+  .rept 16
+    data_cycle %counter
+    .set counter, counter + 1
+  .endr
 
   tst.w       CHIP_ID_REGISTER
   jnz         genShifter_chip_1