diff --git a/Source/DSPSpy/tests/dr_test.ds b/Source/DSPSpy/tests/dr_test.ds
new file mode 100644
index 0000000000..03f9dabbd8
--- /dev/null
+++ b/Source/DSPSpy/tests/dr_test.ds
@@ -0,0 +1,314 @@
+; This test checks the effect of the index looping registers (R8-R11)
+incdir  "tests"
+include "dsp_base.inc"
+
+; Tests done using AR1 = 0x0010, IX1 = 0. LP1 means R09.
+; LP1 = 0
+;   10, 10, 10, 10,
+; LP1 = 1
+;   10, 11, 10, 11,
+; LP1 = 2
+;   10, 12, 11, 13, 12, 11, 13, 12, 11, 13, 12, 11
+; LP1 = 3
+;   10, 13, 12, 11, 10, 13, 12...
+; LP1 = 4
+;   10, 14, 13, 17, 16, 15, 14, 13, 17, 16, 15, 14, 13, ... 
+; LP1 = 5
+;   10, 15, 14, 13, 12, 17, 16, 15, 14, 13, 12, 17, 
+; LP1 = 6
+;   10, 16, 15, 14, 13, 12, 11, 17, 16, 15, 14, 13
+; LP1 = 7
+;   10, 17, 16, 15, .. normal
+; LP1 = 8
+;   10, 18, 17, 1f, 1e, 1d, 1c, 1b, 1a, 19, 18, 17, 1f, 1e, .....
+
+
+; I really don't know how the above could possibly be efficiently implemented in hardware.
+; And thus it's tricky to implement in software too :p
+
+; test using indexing register 1 - 0 is used in send_back
+lri $AR1, #16
+lri $IX1, #32
+lri $R09, #0
+
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #2
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #3
+
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #4
+
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #5
+
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #6
+
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #7
+
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+lri $AR1, #16
+lri $R09, #8
+
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+nx'dr  : $AR1
+call send_back  ; 1
+
+
+lri $R09, #0xFFFF
+
+; We're done, DO NOT DELETE THIS LINE
+jmp end_of_test