(((eax <- 21)
  (call :sum_tail)
  )
 (:sum_tail
  (esp -= 4)
  ((mem esp 0) <- eax)
  (eax <- (print eax))
  (eax <- (mem esp 0))
  (eax -= 2)
  (cjump eax = 1 :done :continue)
  :continue
  (tail-call :sum_tail)
  :done
  (return)))
  