編譯原理學習筆記（十九）~習題：將語句翻譯爲三地址代碼

題目

1．把下列語句翻譯成三地址代碼
while a > 10 do
     if b = 100 then
         while a < 20 do
             a := a + b – 1

解：
(1) if a>10 goto (3)
(2) goto -
(3) if b==100 goto (5) M3.stat
(4) goto (1) M1.stat
(5) if a<20 goto (7) M5.stat
(6) goto (1) M1.stat
(7) t1 := a+b
(8) t2 := t1-1
(9) a := t2
(10) goto (5) M4.stat
(11) goto (1) M1.stat

註釋分析樹：

2．把下列語句翻譯成三地址代碼
if a>10 and c>d then
         if b=100 then a := a / b
         else a := a * b

解：
(1) if a>10 goto (3)
(2) goto –
(3) if c>d goto (5) M1.stat
(4) goto –
(5) if b==100 goto (7) M2.stat
(6) goto (10) M3.stat
(7) t1 := a/b
(8) a := t1
(9) goto -
(10) t2 := a*b
(11) a := t2

註釋分析樹：