問題 5.2

(controller
  (assign p (const 1))
  (assign c (const 1))
test-c
  (test (op >) (reg c) (reg n))
  (branch (label factorial-done))
  (assign t (op *) (reg c) (reg p))
  (assign p (reg t))
  (assign s (op +) (reg c) (const 1))
  (assign c (reg s))
  (goto (label test-c))
factorial-done)

(controller
square-root-loop
  (assign x (op read))
  (assing guess (const 1.0))
test
  (assign a (op square) (reg x))
  (assign b (op -) (reg a) (reg x))
  (assing c (op abs) (reg b))
  (test (op <) (reg c) (const 0.001)))
  (branch (label square-root-done))
  (assign d (op /) (reg x) (reg quess))
  (assign e (op +) (reg guess) (reg d))
  (assign guess (op /) (reg e) (const 2))
  (goto (label test))
square-root-done
  (perform (op print) (reg guess))
  (goto (lable square-root-loop)))

a
(controller
  (assign continue (label expt-done))
expt-loop
  (test (op =) (reg n) (const 0))
  (branch (label return))
  (save continue)
  (assign continue (label after-expt))
  (assign n (op -) (reg n) (const 1))
  (goto (label expt-loop))
after-expt
  (restore continue)
  (assign val (op *) (reg b) (reg val))
  (goto (reg continue))
return
   (assign val (const 1))
   (goto (reg continue))
expt-done)

b
(controller
  (assign counter (reg n))
  (assign product (const 1))
expt-loop
  (test (op =) (reg counter) (const 0))
  (branch (label expt-done))
  (assign counter (op -) (reg counter) (const 1))
  (assign product (op *) (reg b) (reg product))
  (goto (label expt-loop))
expt-done)

;;問題5.7参照

図5.12 「;;Fib(n-2)を計算するよう設定」の前後の
restore continue と
save continue