--- /dev/null
+.include "macros.inc"
+
+start
+
+test_name SUB_1
+mvi r1, 0
+mvi r2, 0
+sub r3, r1, r2
+check_r3 0
+
+test_name SUB_2
+mvi r1, 0
+mvi r2, 1
+sub r3, r1, r2
+check_r3 -1
+
+test_name SUB_3
+mvi r1, 1
+mvi r2, 0
+sub r3, r1, r2
+check_r3 1
+
+test_name SUB_4
+mvi r1, 1
+mvi r2, -1
+sub r3, r1, r2
+check_r3 2
+
+test_name SUB_5
+mvi r1, -1
+mvi r2, 1
+sub r3, r1, r2
+check_r3 -2
+
+test_name SUB_6
+mvi r1, -1
+mvi r2, 0
+sub r3, r1, r2
+check_r3 -1
+
+test_name SUB_7
+mvi r1, 0
+mvi r2, -1
+sub r3, r1, r2
+check_r3 1
+
+test_name SUB_8
+mvi r3, 2
+sub r3, r3, r3
+check_r3 0
+
+test_name SUB_9
+mvi r1, 4
+mvi r3, 2
+sub r3, r1, r3
+check_r3 2
+
+test_name SUB_10
+mvi r1, 4
+mvi r3, 2
+sub r3, r3, r1
+check_r3 -2
+
+test_name SUB_11
+mvi r1, 4
+sub r3, r1, r1
+check_r3 0
+
+test_name SUB_12
+load r1 0x12345678
+load r2 0xabcdef97
+sub r3, r1, r2
+check_r3 0x666666e1
+
+end