;clean registers
;load starting pos and starting pos +1 into memory
;subtract first value (starting pos) from second value (starting pos +1)
;if result is negative or zero, write 0 to x4000
;if positive, loop back and do the same with the next two memory locations
            .ORIG x3000             ;start point
            
            AND R6, R6, #0          ;clean R6
            AND R5, R5, #0          ;clean R5
            AND R4, R4, #0          ;clean R4
            AND R3, R3, #0          ;clean R3
            
LOOP        LD R6, FIRSTPOS         ;block loads first pos into register increments memory value by one and store back
            ADD R6, R6, #1
            ST R6, FIRSTPOS
            
            LD R6, SECONDPOS        ;block loads second pos into register increments memory value by one and store back
            ADD R6, R6, #1
            ST R6, SECONDPOS
            
            LDI R3, FIRSTPOS        ;load values into memory and then create negative out of it
            LDI R4, SECONDPOS
            ADD R4, R4, #0          ;see if the array ends
            BRz FINISH
            NOT R3, R3
            ADD R3, R3, #1
            
            ADD R5, R3, R4          ;add R3 and R4 into R5
            BRp LOOP
            LD R6, ZERO
            STI R6, RESULT
            HALT
FINISH      LD R6, ONE
            STI R6, RESULT
DONE        HALT            

FIRSTPOS .fill x4000
SECONDPOS .fill x4001
RESULT .fill x4000
ONE .fill x0001
ZERO .fill x0000
.END