1 Code Generation (cont’d.)

2 Save to Register A 1. 2 already in Register A, or 2. already in Register A, or 3. 2 and both are not in Register A

3 Code Generation (cont’d.) Node Specifier S( 1 ) save to rA

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5 Code Generation (cont’d.)

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7 Code Generation (cont’d.) 9 and 10 S( ) := S( ) = S(SUMSQ) REGA = S( ) <> rA =S(MEAN)

8 Code Generation (cont’d.) 10

9 S( 2 ) <> rA = S(MEAN) Call GETA( 2 ) GETA(SUMSQ) Generate [SUB S(MEAN)=T2] S( 1 ) := rA REGA := 1

10 Code Generation (cont’d.) 11 S( ) := S( ):= S(SUMSQ) S( ) <> rA S( ) := S(MEAN l )

11 Code Generation (cont’d.) 11 S( 2 ) <> rA S( ) <> rA Call GETA(MEAN) Generate [MUL MEAN] S(MEAN) := rA REGA:= MEAN

12 Code Generation (cont’d.) 11 S( 2 ) <> rA Call GETA(SUMSQ) Generate [DIV #100] S( 1 ) := rA REGA := 1

13 Code Generation (cont’d.) 12 S( ) := S(SUMSQ) S( ) := S(MEAN l ) S( ) := S(MEAN r ) S( ) := S(#100)

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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 = MEAN S(SUMSQ) <> rA = S(MEAN) Generate [STA T2] S(MEAN) = T2 Generate [LDA S(SUMSQ)=T1] S(SUMSQ) := rA REGA := 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.)

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31 LDASUMSQ DIV#100 STAT1 LDAMEAN MULMEAN STAT2 LDAT1 SUBT2 STAT3 LDAT3 STAVARIANCE

32 T2 LDAMEAN MULMEAN STAT2 LDASUMSQ DIV#100 STAT1 LDAT1 SUBT2 STAT3 LDAT3 STAVARIANCE

33 T2

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37 3*(6-1)=3*5=15

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39 3*(I-1) Content of Address of A A(3*(I-1))=5

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41 3*((I-0)*(6-1+1)+(J-1))=5

42 3*((I-1)*(10-1+1)+(2J-1-1)) 3*(i1(i8)*10 3*(i2(i9) +i3(i10)-1-1 +i4(i11)-1 +i5 3*i6(i12) i7(i13)

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46 Machine-Independent Compiler Features

47 Machine-Independent Compiler Features Storage Allocation Static Allocation: cannot be used for recursive call Dynamic Allocation: Activation Record

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55 P-Code Compliers

56 Compiler-Compilers

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