.entry start

loop:
  ; If the counter is less or equal to 1, finish
  cmp R3, 1
  jle @end

  sub R3, 1
  mul R1, R3
  jmp @loop

end:
  ret

start:
  ; Find factorial for the initial value of R3,
  load R3, 5

  ; Copy the initial value of R3 to R1,
  ; R1 is our factorial result
  load R1, R3
  call @loop
  ; Display the message and exit
  store @1000, R1
  inspect @1000
  halt