Sweet16

; Sweet16 Factorial Program
; Compute factorial of a number

SET R1, 5        ; Load 5 into R1 (number to compute factorial of)
SET R2, 1        ; Load 1 into R2 (accumulator for result)
SET R3, 1        ; Load 1 into R3 (counter)

LOOP:
LD R3            ; Load counter
SUB R1           ; Subtract input number
BGT END          ; If counter > input, we're done
LD R2            ; Load accumulator
MUL R3           ; Multiply by counter
ST R2            ; Store back to accumulator
INC R3           ; Increment counter
BR LOOP          ; Branch back to loop

END:
LD R2            ; Load result
RTS              ; Return to system