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Trailing-Edge - PDP-10 Archives - BB-H138A-BM - 3a-sources/gt1n.bli
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!THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY ONLY BE USED
!  OR COPIED IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE.
!
!COPYRIGHT (C) 1977,1978 BY DIGITAL EQUIPMENT CORPORATION
!FILENAME:	H1GTRE.BLI
!DATE:		24 MAY 73	MGM/FLD

%3.%	GLOBAL BIND H1GTV=2;	!MODULE VERSION NUMBER

!  REVISION HISTORY:
!
!  9-19-77  ROUTINE GENGRAPH IS MODIFIED TO FIX BUG#46,
!           NESTED IF THEN ELSE EXPRESSIONS.(COMMON SUB-
!           EXPRESSIONS).
!
!   6-2-77   ROUTINE GTGOTM IS MODIFIED TO FIX BUG #11
!            IN BLISS10.DOC.GADD AND GSTO WAS REPLACED
!            BY GOTM AND DID NO GOOD. THIS WAS DONE FOR OPTIMIZATION.
!	     NOW IN THIS CASE FORGET ABOUT OPTIMIZATION.
!            CASE IS X[]_.X[]+2;.
!

! GRAPH TABLE GENERATION AND INTERPRETATION ROUTINES
!----------------------------------------------------



ROUTINE TREGP(X)= (((.X AND NOT(#37^16)) EQL 0) AND (.X<RTEF> GEQ 16));

%3.1%	GLOBAL ROUTINE FIXOCCF(L,F,T)=
    BEGIN LOCAL YR; 
    !  THIS ROUTINE FIXES THE <OCCF> AND <USEF> FIELDS
    !  IN THOSE CASES WHERE A NODE IS RE-FOUND BEFORE ITS
    !  USE HAS GONE TO ZERO.
    INCR I FROM .F TO .T DO
	IF .GT[.L,.I]<LEFTHALF> EQL GTLEX THEN
	    BEGIN
	    GT[.GT[.L,.I]<LINKF>,0]<OCCF> _
	        MAXER(.GT[.GT[.L,.I]<LINKF>,0]<OCCF>-1,0);
	    IF .GT[.GT[.L,.I]<LINKF>,0]<RESULTF> THEN
		IF (YR_TREGNUM(.GT[.GT[.L,.I]<LINKF>,1])) GEQ 16  THEN
		    DUN(.YR);
	    END
	ELSE IF(YR_TREGNUM(.GT[.L,.I])) GEQ 16 THEN DUN(.YR);
    END;

ROUTINE FIXALLOCCF(L)=
    BEGIN LOCAL N; N_.GT[.L,0]<SUBNF>+2;
    INCR I FROM 3 TO .N DO
	IF .GT[.L,.I]<LEFTHALF> EQL GTLEX THEN
         IF NOT .GT[.GT[.L,.I]<LINKF>,0]<RESULTF> THEN
	    FIXALLOCCF(.GT[.L,.I]<LINKF>);
    FIXOCCF(.L,3,.N)
    END;

%3.1%	GLOBAL ROUTINE MAKGT(N,OP,PTR,DIR)=
    BEGIN LOCAL S,L,GTL;
    !  THIS ROUTINE BUILDS A GRAPH-TABLE ENTRY IN CASE THERE
    !  WASN'T ONE. THE SUBNODE ENTRIES ARE POINTED TO BY THE
    !  VARIABLE PTR -- THERE DIRECTION RELATIVE TO PTR IS KEPT
    !  IN DIR.
    S_2+.N/2;
    GT[L_GETSPACE(.S),0]_ .GRAPHHEAD[GTL_GTHASH(.OP)];
    GRAPHHEAD[.GTL]_.L;
    GT[.L,0]<OCCF>_1;
    GT[.L,0]<SUBNF>_.N;
    GT[.L,1]_0;
    GT[.L,2]_.OP;
    INCR I FROM 0 TO .N-1 DO
	    GT[.L,.I+3]_@(.PTR+.I*.DIR);
    .L
    END;
ROUTINE GTGOTM(O1,O2,OP)=
    BEGIN LOCAL L1,L2,L3,L4,L5; BIND NNDM=7^33;
    !
    ! THIS ROUTINE ATTEMPTS TO RECOGNIZE AND OPTIMIZE THE
    ! CASES IN WHICH A 'TO-MEMORY' OPERATOR MAY BE 
    ! GENERATED. A SPECIAL GT-NODE IS BUILT IN THESE CASES
    ! SO THAT A SPECIAL CODE GENERATOR, 'GOTM', WILL BE
    ! BE CALLED.
    !

    ROUTINE OKOP(X)=(.X<HPRIORITY> GTR #21 AND .X<HPRIORITY> LSS #37
		      AND .X<HPRIORITY> NEQ #30);
    ROUTINE NNTYPE(X)=(.X<LEFTHALF> EQL HNEG OR .X<LEFTHALF> EQL HNOT);
    ROUTINE DOTTYPE(X)= .X<HPRIORITY>EQL #21;
    FUNCTION FIND(E,ATT)=
	BEGIN
	IF NNTYPE(.GT[.ATT,2]) THEN
	    IF .GT[.ATT,3]<LEFTHALF> NEQ GTLEX
		THEN RETURN 0 ELSE ATT_.GT[.ATT,3]<LINKF>;
        L5_IF .GT[.ATT,3]<LEFTHALF> EQL GTLEX
             THEN .GT[.ATT,3]<LINKF> ELSE 0;
	IF DOTTYPE(.GT[.ATT,2]) THEN 
	  (IF .L5 NEQ 0 THEN NOT DOTTYPE(.GT[.L5,2]) ELSE 1) AND
	  (.GT[.ATT,3] EQL .E)
	ELSE 0
	END;



    IF .OP<LEFTHALF> EQL HSTO THEN
	IF (.O1 AND NNDM) EQL 0 THEN
	    IF .O2<LEFTHALF> EQL GTLEX THEN
		IF OKOP(.GT[L1_.O2<LINKF>,2]) THEN
		  IF NOT(.GT[.L1,0]<RESULTF>) THEN
		    BEGIN  L4_4-.GT[.L1,2]<HUNARY>;
		    IF .GT[.L1,.L4]<LEFTHALF> EQL GTLEX THEN
			IF FIND(.O1,.GT[.L1,.L4]<LINKF>) THEN
			    BEGIN ! PHEW--WE GOT ONE
				! DONOT BOTHER TO OPTIMIZE X[1]_.X[1]+5
				! BECAUSE IT DOES NOT ANYWAY.
				!IT GOES TO GOTM,GADD,GSTO AND GOING TO GOTM UNNECESSARY
				!  5_27_77
			     IF .STUTYPE EQL 1 AND .O1<LEFTHALF> EQL GTLEX
			       THEN (STUTYPE_0; RETURN 0);
			    L2_MAKGT(4,NGOTM<0,0>,GT[.L1,2],+1);
			    GT[.L2,4]_ IF .GT[.L1,.L4]<LEFTHALF> EQL GTLEX
				THEN .GT[.GT[.L1,.L4]<LINKF>,0]<OCCF> LEQ 1 ELSE 1;
			    GT[.L2,4]<LEFTHALF>_.L5;
			    GT[.L2,5]_.GT[.L1,.L4];
			    GT[.L2,6]_ IF .OP<HUNARY>
				THEN 0 ELSE .GT[.L1,3];
			    GT[.L1,0]<OCCF>_MAXER(.GT[.L1,0]<OCCF>-1,0);
			    RETURN (GTLEX^18 + .L2)
			    END;
		    END;
    END;
%3.1%	GLOBAL ROUTINE GENGRAPH(OP,N)=
    BEGIN LOCAL S,GTL,L,X,XR,YR; 
	  EXTERNAL NOIFOPT;
    !    
    !    THIS ROUTINE GENERATES THE GRAPH TABLE AND RETURNS A
    !    GRAPH-TABLE LEXEME FOR THE (SUB) TREE(S).  BEFORE A
    !    NEW ENTRY IS MADE THE EXISTING TABLE IS SEARCHED
    !    FOR A COMMON SUB-EXPRESSION, AND, IF FOUND, THE LEXEME
    !    FOR THIS ENTRY IS RETURNED AFTEN APPROPRIATE ADJUSTMENT
    !    OF THE OCCURRENCE COUNTS.
    !
    IDCHECKER(OP,.N);
    IF NOT(.CODETOG) THEN RETURN LITLEXEME(0);

    IF NOT .NOIFOPT				%9-19-77% 
    THEN
    BEGIN
    L_.GRAPHHEAD[GTL_GTHASH(.OP)];
    IF (X_GTGOTM(@(OP-2),@(OP-1),@OP)) NEQ 0 THEN RETURN .X;
    WHILE .L NEQ 0 DO
	BEGIN
	IF .OP EQL .GT[.L,2] THEN
	    BEGIN
	    X_ INCR I FROM 1 TO .N DO
	    	IF @(OP-.I) NEQ .GT[.L,.I+2] THEN BREAK 0
			ELSE IF TREGP(@(OP-.I)) THEN BREAK 0;
	    IF .X NEQ 0 THEN
		!SUCCESS, WE HAVE FOUND A MATCHING ENTRY.
		    BEGIN
		    IF (GT[.L,0]<OCCF>_.GT[.L,0]<OCCF>+1) GTR 1^8-1 THEN ERROR(.NSYM,#773);
		    IF .GT[.L,0]<RESULTF> THEN
			IF (XR_TREGNUM(.GT[.L,1])) GEQ 16 THEN
			    INCRUSEN(.XR);
		IF .GT[.L,0]<RESULTF> THEN FIXALLOCCF(.L) ELSE
		IF .GT[.L,0]<OCCF> GTR 1 THEN FIXOCCF(.L,3,.N+2);
		    RETURN (GTLEX^18+.L)
		    END
	    END;
	L_.GT[.L,0]<LINKF>;
	END;
    END;

    !IF WE REACH THIS POINT WE HAVE SEARCHED THE ENTIRE GRAPH TABLE (SUB-LIST)
    ! AND HAVE NOT FOUND A COMMON SUBEXPRESSION.  THEREFORE WE CREATE
    ! A GRAPH TABLE ENTRY AND LINK IT INTO THE LIST.
    !
    MAKGT(.N,.OP,OP-1,-1)+GTLEX^18
    END;
%3.1%	GLOBAL ROUTINE GTPURGE(TOG)=
    BEGIN LOCAL L,L1,L2; 
    !
    !    THIS ROUTINE PURGES THE GRAPH TABLE OF ALL ENTRIES WHICH
    !    DO NOT HAVE VALID RESULTS STILL HELD IN REGISTERS OR
    !    ARE CONSTITUENTS OF SUCH RESULTS.  IT OPERATES BY FIRST
    !    MARKING ALL SUCH ENTRIES AND THEN RELEASING ALL UNMARKED
    !    ENTRIES.
    !
    !    DEPENDING ON THE VALUE OF 'TOG' WE  DO A MORE OR
    !    LESS DRASTIC PURGE (2=>MORE,  0=>LESS). IN PARTICULAR
    !        TOG=0:	WE SAVE ANY ENTRY WITH A RESULT
    !    		STILL CONTAINED IN A REG.
    !        TOG=1:	WE SAVE ONLT THOSE ENTRIES WITH A NON-ZERO
    !    		'SAVE' FIELD -- IE, THOSE ENTRIES BEING
    !    		PRESERVED ACROSS A 'FORK'.
    !	     TOG=2:	WE SAVE ONLY THOSE ENTRIES WITH A 
    !			SAVE FIELD VALUE GREATER THAN ONE,
    !			THIS IS USUALLY THE CASE JUST BEFIRE
    !			TERMINATING A FORK.
    !
    ROUTINE GTMARK(GTE)=
	BEGIN LOCAL F;
	!
	!  THIS ROUTINE PROPAGATES MARK BITS DOWN AND
	!  FUNNYBITS BACK UP TO PARENTS.
	!
	F_.GT[.GTE,0]<FUNNYBIT>;
	IF .GT[.GTE,0]<MARKBIT> THEN RETURN .F;
	INCR I FROM 3 TO .GT[.GTE,0]<SUBNF>+2 DO
	    IF .GT[.GTE,.I]<LEFTHALF> EQL GTLEX THEN
		F_.F OR GTMARK(.GT[.GTE,.I]<LINKF>);
	GT[.GTE,0]<MARKBIT>_1;
	GT[.GTE,0]<FUNNYBIT>_.F;
	.F
	END;

    INCR I FROM 0 TO GTMASK DO
	BEGIN
	L_.GRAPHHEAD[.I]; 
	WHILE .L NEQ 0 DO
	    BEGIN
	    IF .GT[.L,0]<OCCF> NEQ 0 THEN GTMARK(.L) ELSE
	    CASE .TOG OF
		SET
		IF .GT[.L,0]<ROSF> NEQ 0 THEN
		  IF NOT .GT[.L,0]<RESULTF> THEN GTMARK(.L) ELSE
		  IF TREGNUM(.GT[.L,1]) GEQ 16 THEN GTMARK(.L);
		IF .GT[.L,0]<SAVGEF> GTR 0 THEN GTMARK(.L);
		IF .GT[.L,0]<SAVGEF> GTR 1 THEN GTMARK(.L);
		TES;
	    L_.GT[.L,0]<LINKF>;
	    END;
	END;

    INCR I FROM 0 TO GTMASK DO
	BEGIN
	L_.GRAPHHEAD[.I];  GRAPHHEAD[.I]_0;
	WHILE .L NEQ 0 DO
	    BEGIN
	    L1_.GT[.L,0]<LINKF>;
	    IF .GT[.L,0]<MARKBIT>
		THEN
		    BEGIN
		    GT[.L,0]<LINKF>_.GRAPHHEAD[.I]; GRAPHHEAD[.I]_.L;
		    IF .GT[.L,0]<FUNNYBIT> THEN
			BEGIN
			GT[.L,0]<RESULTF>_0; GT[.L,0]<FUNNYBIT>_0;
			IF (L2_TREGNUM(.GT[.L,1])) GEQ 16 THEN
				SCAN( CTRCTH(.L2),
				    .L,GTLEXP,ERASE)
			END;
		    GT[.L,0]<MARKBIT>_0;
		    END
		ELSE
		    BEGIN
		    IF (L2_TREGNUM(.GT[.L,1])) GEQ 16 THEN
			SCAN ( CTRCTH(.L2),
			    .L,GTLEXP,ERASE);
		    RELEASESPACE(.L,2+.GT[.L,0]<SUBNF>/2)
		    END;
	    L_.L1
	    END;
	END;
    END;
ROUTINE GTID(TOG)=
    BEGIN LOCAL L,NS,OC,RN;
    !
    !    THIS ROUTINE INCREMENTS (TOG=1) OR DECREMENTS (TOG=-1)
    !    ALL 'SAVGE' FIELDS IN THE GRAPH TABLE.  THIS IS DONE TO
    !    PRESERVE THE EXISTING GRAPH TABLE ACROSS
    !    FORKS (E.G. IF-THEN-ELSE).
    !
    INCR I FROM 0 TO GTMASK DO
	BEGIN
	L_.GRAPHHEAD[.I];
	WHILE .L NEQ 0 DO
            BEGIN
	    IF (NS_.GT[.L,0]<SAVGEF>+.TOG) GTR 1^7-1 THEN ERROR(.NDEL,#771) ELSE
	    IF .NS GEQ 0