! File:   TRY.BLI
!
!    This work was supported by the Advanced Research
!    Projects Agency of the Office of the Secretary of
!    Defense (F44620-73-C-0074) and is monitored by the
!    Air Force Office of Scientific Research.


MODULE TRY(TIMER=EXTERNAL(SIX12),GLOROUTINES)=
BEGIN
REQUIRE COMMON.BEG;
REQUIRE GTST.BEG;
REQUIRE GTX.BEG;
REQUIRE LDSF1.BEG;
REQUIRE FLOW.BEG;
REQUIRE TN.BEG;
BEGIN
REQUIRE TRY.BEG;

BIND	REGTOOCROWD = 99;	! FROM ERROR.BEG
EXTERNAL ERRINFO,WARNEM;

EXTERNAL GETTN;

MACRO CONTINUE=EXITBLOCK$;


!	2. - FITTING
!
!		THESE ROUTINES DETERMINE WHETHER IT IS POSSIBLE
!		TO PLACE A PARTICULAR TN INTO A PARTICULAR
!		LOCATION (REGISTER OR WHATEVER). THE TN'S ALREADY
!		ASSIGNED TO A LOCATION ARE REPRESENTED BY A TN-REP
!		LIST ASSOCIATED WITH THAT LOCATION. THE 'LIFE SPAN'
!		INFO DETERMINED BY THE TL ROUTINES IS USED TO
!		DETERMINE THE POSSIBILITY OF FITTING THE TN INTO
!		THE LOCATION.
!

	    ROUTINE TRYFIT(TN,LST)=
		BEGIN
		MACRO SAVEQ=Q_.TR$,
		      OVERLAPFON=
			(((.T[FONFU]-.TN[FONLU])*(.TN[FONFU]-.T[FONLU])) GEQ 0)$;
		MAP GTVEC TN, TNREPR LST;
		LOCAL GTVEC T;
		REGISTER Q;
		FORALLTN(T,.LST,
		    BEGIN
		    BIND ZQZQ=45;
		    IF .T[LONLU] LSS .TN[LONFU] THEN (SAVEQ;EXITBLOCK);
		    IF .T[LONFU] GTR .TN[LONLU] THEN
			(LINK(TNREP(.TN),.Q);NOTEBOUND(TN,.LST);SUCCESS);
		    IF OVERLAPFON THEN
			IF (.T[TNPERMIT] NEQ .TN) AND (.T NEQ .TN[TNPERMIT]) THEN FAIL;
		    IF .T[LONFU] LSS .TN[LONFU] THEN SAVEQ;
		    END)
		END;

!	3. - OPENING
!
!		THESE ROUTINES ALLOW 'OPENING' AND CLOSING
!		LOCATIONS. NOTE THAT CLOSING     IS ACCOMPLISHED
!		BY MAKING IT APPEAR THAT THE LOCATION IS 'IN-USE'
!		OVER AN INFINITE LIFE SPAN.
!

	    ROUTINE OPENLIST(L)=
		BEGIN
		MAP TNREPR L;
		LOCAL GTVEC BF:BT;
		BF_GETTN();
		BT_GETTN();
		BF[LONFU]_BF[LONLU]_BF[FONFU]_BT[FONFU]_GENESIS;
		BT[LONLU]_BT[LONFU]_BF[FONLU]_BT[FONLU]_ETERNITY;
		BF[REQD]_BT[REQD]_IGREQDB;	! THESE ARE DUMMY TNS
		LINK(TNREP(.BF),.L[LLINK]);
		LINK(TNREP(.BT),.L[LLINK])
		END;


	    ROUTINE CLOSELIST(LST,WHEN)=
		BEGIN
		MAP TNREPR LST;
		LOCAL GTVEC L;
		LST_.LST[LLINK];
		L_.LST[TNPTR];
		IF .L[LONFU] GTR .WHEN THEN L[LONFU]_.WHEN;
!		IF .L[FONFU] GTR .FON THEN L[FONFU]_.FON;
		NOVALUE
		END;


	    ROUTINE REOPEN(LST,ATLON,ATFON)=
		BEGIN
		MAP TNREPR LST;
		LOCAL GTVEC L;
		IF NOT ISOPEN(.LST[TNLINKWORD]) THEN
		    (OPENLIST(.LST); CLOSELIST(.LST,1));
		LST_.LST[LLINK];
		L_.LST[TNPTR];
		L[LONLU]_IF .L[LONFU] LSS .ATLON THEN .ATLON-1 ELSE .L[LONFU];
!		L[FONLU]_IF .L[FONFU] LSS .ATFON THEN .ATFON-1 ELSE .L[FONFU];
		L_GETTN();
		L[REQD]_IGREQDB;	! DUMMY TN
		L[LONLU]_L[FONLU]_L[LONFU]_ETERNITY;
		L[FONFU]_GENESIS;
		LINK(TNREP(.L),.LST)
		END;


!
!	THE FOLLOWING SECTIONS, B-D, DEFINE THE PRIMITIVES
!	FOR VARIOUS TYPES OF LOCATIONS WHICH MAY BE USED TO
!	HOLD TEMP RESULTS.
!
!
!
!
!
!   B. - REGISTERS
! ------------------------------------------------

    ROUTINE ISREGLST(LST)=
	BEGIN
	LST<LEFTPART>_0;
	IF .LST GEQ REGS[0]<0,0>
	    THEN IF .LST LEQ REGS[5]<0,0>
		THEN RETURN 1;
	0
	END;

    ROUTINE TRYSPREG(T,R)=
	BEGIN
	! ASSIGN T TO THE SPECIFIC REGISTER R.
	IF NOT (ISOPEN(.REGS[.R])) THEN OPENREG(.R);
	IF NOT TRYFIT(.T,REGS[.R]<0,0>) THEN
		(MAP GTVEC T;
		 ERRINFO[0]_.R;
		 WARNEM(0,REGTOOCROWD);
		 T[BNDLSTHDR]_REGS[.R]<0,0>;
		 MARKTN(.T,BNDREG);
		 T[REGF]_.R)
	END;

    ROUTINE TRYOPREG(T)=
	BEGIN
	! TRY THE OPEN REGISTERS
	DECR I FROM 5 TO 0 DO
	    IF ISOPEN(.REGS[.I]) THEN
	      IF NOT .RESERVED[.I,1] THEN
		IF TRYFIT(.T,REGS[.I]<0,0>) THEN SUCCESS;
	FAIL
	END;

    ROUTINE TRYCLREG(T)=
	BEGIN
	! TRY TO OPEN A REGISTER
	INCR I FROM 0 TO 5 DO
	    IF NOT (ISOPEN(.REGS[.I])) THEN
	      IF NOT .RESERVED[.I,1] THEN
		(OPENREG(.I); IF TRYFIT(.T,REGS[.I]<0,0>) THEN SUCCESS);
	FAIL
	END;

!   C. - STATIC TEMPS
! ------------------------------------------------

    ROUTINE TRYOPSTEMPS(T)=
	BEGIN
	! TRY THE OPEN STATIC TEMPS
	INCR I FROM 0 TO .STEMPS[CURD] DO
	    IF TRYFIT(.T,STEMPS[LSELEM(.I)]<0,0>) THEN SUCCESS;
	FAIL
	END;

    ROUTINE TRYCLSTEMPS(T)=
	BEGIN
	! OPEN A NEW STATIC TEMP
	PUSHSTK(STEMPS);
	OPENLIST(STEMPS[TOS]);
	TRYFIT(.T,STEMPS[TOS]<0,0>)	! NOTE THIS WILL (SHOULD) ALWAYS WORK
	END;

!   D. - DYNAMIC TEMPS
! ------------------------------------------------

    ROUTINE TRYSPDYTEMP(T,N)=
	BEGIN
	IF .N LSS 0 OR .N GTR .DTEMPS[CURD] THEN FAIL
	ELSE TRYFIT(.T,DTEMPS[LSELEM(.N)]<0,0>)
	END;

    ROUTINE OPENDYTEMP(T,OLON,OFON)=
	BEGIN
	MAP GTVEC T;
	IF (DTEMPS[CURD]_.DTEMPS[CURD]+1) GTR .DTEMPS[MAXD] THEN
	    (DTEMPS[MAXD]_.DTEMPS[CURD]; NULLLST(DTEMPS[TOS]));
	REOPEN(DTEMPS[TOS],.OLON,.OFON);
	TRYFIT(.T,DTEMPS[TOS]<0,0>);
	MARKTN(T,BNDPUSH)

	END;

    ROUTINE CLOSEDYTEMPS(TOO)=
	BEGIN
	IF .TOO GEQ .DTEMPS[CURD] THEN RETURN;
	DECR I FROM .DTEMPS[CURD] TO .TOO+1
	  DO CLOSELIST(DTEMPS[LSELEM(.I)],.LON);
	DTEMPS[CURD]_.TOO
	END;


    ROUTINE TRYDYTEMPS(T)=
	BEGIN
	! TRY THE DYNAMIC TEMPS OPENED BY TLA
	DECR I FROM .DTEMPS[MAXD] TO 0 DO
	    IF TRYFIT(.T,DTEMPS[LSELEM(.I)]<0,0>) THEN SUCCESS;
	FAIL
	END;

    ROUTINE MUSTBETOP(TN,LST)=
	!
	! PREDICATE WHICH DETERMINES WHETHER, IF TEMP-NAME 'TN'
	! WERE ALLOCATED TO DYTEMP-LIST 'LST', IT WOULD ALWAYS
	! BE ADDRESSED AS '@SP' (RATHER THAN 'N(SP)', WITH N NON-ZERO).
	!
	BEGIN
	MAP GTVEC TN;
	LOCAL MARK,LSTHDR L,GTVEC T;

	IF .LST EQL DTEMPS[LSELEM(.DTEMPS[MAXD])]<0,0> THEN RETURN 1;
	L_0;
	INCR I FROM 1 TO .DTEMPS[MAXD] DO
	  IF .LST EQL DTEMPS[LSELEM(.I-1)]<0,0>
	    THEN EXITLOOP L_DTEMPS[LSELEM(.I)]<0,0>;
	IF .L EQL 0 THEN RETURN 0;
	MARK_.TN[LONFU];
	FORALLTN(T,.L,
	  (BEGIN DUMMYBLOCK;
		IF .T[LONLU] LSS .TN[LONFU] THEN CONTINUE;
		IF .T[LONFU] GTR .TN[LONLU] THEN RETURN 0;
		IF .T[LONFU] GTR .MARK THEN RETURN 0;
		IF .T[REQD] NEQ IGREQDB THEN RETURN 0;
		IF (MARK_.T[LONLU]) GEQ .TN[LONLU] THEN RETURN 1
	   END))
	END;

END
END ELUDOM