# Pine factorial
# dbg lne on

mov s 'done'
mov ec 0

lbl main
  run input
  run factorial
  run print
  run success

lbl input
  mov fac 0
  mov zero 0
  mov q 'factorial calculator'

  prt q
  ask fac
  cmp fac zero
  jle error
  psh fac
ret

lbl factorial
  mov inc 1
  mov index 1
  mov res 1
  mov fac 0
  pop fac

  lbl loop
  cmp index fac
  jgt end
  mlt res index
  add index inc
  jmp loop
  lbl end
  psh res
ret

lbl print
  mov res '> '
  mov val ''
  pop val

  add res val
  prt res
ret

lbl success
  # prt s
  ext ec

lbl error
  mov s 'error: num must be > 0'
  mov ec 1

  prt s
  ext ec