1

Code Generation (cont’d.)

2

Code Generation (cont’d.)

Save to Register A 1. <term>2 already in Register A, or2. <factor> already in Register A, or3. <term>2 and <factor>both are not in Register A

3

Code Generation (cont’d.)

Node Specifier S(<term>1)save to rA

4

5

Code Generation (cont’d.)

6

Code Generation (cont’d.)

7

Code Generation (cont’d.) 9 and 10

S(<exp>) := S(<term>) = S(SUMSQ)

REGA = <exp>

S(<exp>) <> rA =S(MEAN)

8

Code Generation (cont’d.) 10

9

Code Generation (cont’d.) 10

S(<exp>2) <> rA = S(MEAN)

Call GETA(<exp>2) GETA(SUMSQ)

Generate [SUB S(MEAN)=T2]

S(<exp>1) := rA

REGA := <exp>1

10

Code Generation (cont’d.) 11

S(<term>) := S(<factor>):= S(SUMSQ)

S(<term>) <> rA

S(<term>) := S(MEANl)

11

Code Generation (cont’d.) 11

S(<term>2) <> rA

S(<factor>) <> rA

Call GETA(MEAN)

Generate [MUL MEAN]

S(MEAN) := rA

REGA:= MEAN

12

Code Generation (cont’d.) 11

S(<term>2) <> rA

Call GETA(SUMSQ)

Generate [DIV #100]

S(<term>1) := rA

REGA := <term>1

13

Code Generation (cont’d.) 12

S(<factor>) := S(SUMSQ)

S(<factor>) := S(MEANl)

S(<factor>) := S(MEANr)

S(<factor>) := S(#100)

14

15

Code Generation (cont’d.)

REGA = NULL

Generate [LDA SUMSQ]

S(SUMSQ) := rA

REGA := SUMSQ

REGA <> NULL = SUMSQ

S(MEAN) <> rA = S(SUMSQ)

Generate [STA T1]

S(SUMSQ) = T1

Generate [LDA MEAN]

S(MEAN) := rA

REGA := MEAN

REGA <> NULL = MEANS(SUMSQ) <> rA = S(MEAN)Generate [STA T2]S(MEAN) = T2Generate [LDA S(SUMSQ)=T1]S(SUMSQ) := rAREGA := SUMSQ

16

Code Generation (cont’d.)

I

17

Code Generation (cont’d.) 1, 2, and 3

18

Code Generation (cont’d.) 4, 5, and 7

19

8, 14, 15

20

Code Generation (cont’d.) 16 and 17

21

Code Generation (cont’d.)

22

Code Generation (cont’d.)

23

24

25

26

27

28

29

30

31

LDA SUMSQDIV #100STA T1LDA MEANMUL MEANSTA T2LDA T1SUB T2STA T3LDA T3STA VARIANCE

32

T2

T2

LDA MEANMUL MEANSTA T2LDA SUMSQDIV #100STA T1LDA T1SUB T2STA T3LDA T3STA VARIANCE

33

T2

T2

34

35

36

37

3*(6-1)=3*5=15

38

39

3*(I-1)

Content of Address of A A(3*(I-1))=5

40

41

3*((I-0)*(6-1+1)+(J-1))=5

42

3*((I-1)*(10-1+1)+(2J-1-1))3*(i1(i8)*103*(i2(i9) +i3(i10)-1-1

+i4(i11)-1 +i53*i6(i12)i7(i13)

43

44

45

46

Machine-Independent Compiler Features

47

Machine-Independent Compiler Features Storage Allocation

Static Allocation: cannot be used for recursive call

Dynamic Allocation: Activation Record

48

49

50

51

52

53

54

55

P-Code Compliers

56

Compiler-Compilers

57

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