; Author:      Andres Calderon Jaramillo
; Description: Solves the problem in slide #28 in Lecture13(C5)
;              (computes the sum of the first 12 integers starting at 1)
;

          .ORIG x3000         ; Program starts at x3000
          
          AND R3, R3, #0      ; Initialize R3 to 0 (will contain the sum)
          
          AND R2, R2, #0      ; Initialize R2 to 12 (will act as loop counter)
          ADD R2, R2, #12     ;
          
Loop      BRz Exit            ; Exit the loop if R2 is 0
          ADD R3, R3, R2      ; R3 = R3 + R2
          ADD R2, R2, #-1     ; Decrement R2 (modifies condition code)
          BR Loop             ; Go to the beginning of the loop
          
Exit      HALT                ; End the program (R3 now contains the sum)
          
          .END