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Trailing-Edge - PDP-10 Archives - AP-D480B-SB_1978 - sta0.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) 1973,1977 BY DIGITAL EQUIPMENT CORPORATION
!AUTHOR: F.J. INFANTE/HPW/ D. B. TOLMAN/DCE
MODULE STA0(RESERVE(0,1,2,3),SREG=#17,FREG=#16,VREG=#15,DREGS=4,GLOROUTINES)=
BEGIN

SWITCHES NOLIST;
REQUIRE LEXNAM.BLI;
REQUIRE FIRST.BLI;
REQUIRE TABLES.BLI;
REQUIRE META72.BLI;
REQUIRE ASHELP.BLI;
SWITCHES LIST;




GLOBAL BIND STA0V = 4^24+2^18+46;		!VERSION DATE: 09-DEC-75


%(
REVISION HISTORY

44	-----	-----	CATCH ILLEGAL LIST DIRECTED RANDOM ACCESS

45	-----	-----	MOVE DO INDEX MODIFICATION CHECK TO NAMSET SO THAT
			IT WILL GET ALL CASES OF MODIFICATION
46	336	17259	CHECK FOR ILLEGAL I/O LIST WITH NAMELIST

)%

!THE NUMBER IN COMMENT'S IS THE STATEMENTS LOCATION
!IN THE HASH TABLE .
FORWARD
	MULTIASGN,
	ASSIGNMENT,	! ASSIGNMENT
%  1%	PUNCSTA,	!PUNCH 
% 38%	CALLSTA,	!CALL 
% 49%	GOTOSTA,	!GOTO 
% 53%	PAUSSTA,	!PAUSE 
% 57%	RETUSTA,	!RETURN 
% 73%	ACCESTA,	!ACCEPT 
% 78%	READSTA,	!READ 
% 90%	WRITSTA,	!WRITE 
% 98%	CONTSTA,	!CONTINUE 
%109%	ASSISTA,	!ASSIGN 
%114%	STOPSTA;	!STOP


	GLOBAL ROUTINE 
MULTIASGN ( LEFTSIDE ) =
BEGIN
	REGISTER BASE R1:R2;
	EXTERNAL NEWENTRY %()%,SAVSPACE %(SIZE,LOC)%,STK,ASGNTYPER,LABLOFSTATEMENT;
	EXTERNAL WARNLEX;
	MACRO
	EXPRBASE=1,0,FULL$;
	NAME_IDOFSTATEMENT_ASGNDATA;NAME<RIGHT>_SORTAB;
	R1_NEWENTRY();
	R2_.STK[0];
	R1[RHEXP]_.R2[ELMNT1] % EXPRESSION POINTER %;
	R1[LHEXP]_R2_.LEFTSIDE;
	ASGNTYPER(.R1);	!CHECKING FOR ASSIGNMENT CONVERSION
	R2 _ .R1[LHEXP]; !RESTORING EXP PTR INCASE OF TYPE CONVERSION NODE INSERTED
	IF .R2[OPRCLS] EQL DATAOPR THEN R1[A1VALFLG]_1 ELSE R2[PARENT] _ .R1;
	R2 _ .R1[RHEXP]; !RESTORE RH EXP PTR
	IF .R2[OPRCLS] EQL DATAOPR  THEN R1[A2VALFLG]_1
		 ELSE ( R2[PARENT] _ .R1; IF .R2[FNCALLSFLG] THEN R1[FNCALLSFLG] _1);
	SAVSPACE(.STK[0]<LEFT>,@STK[0])
END;


	GLOBAL ROUTINE 
ASSIGNMENT  =
BEGIN
	EXTERNAL NAMSET,NAMDEF;
	REGISTER BASE T1:T2;
	EXTERNAL STK,SP,NEWENTRY %()%,SAVSPACE %(SIZE,LOC)%,MULTIASGN %()%,PROGNAME;
!------------------------------------------------------------------------------------------------------------------
!	SYNTAX RETURNS A LIST POINTER (COUNT^18+LOC) IN STK[0]. THIS LIST CONTAINS:
!
!	IDENTIFIER(20^18+LOC) - TO BE ASSIGNED
!	POINTER TO LOGICAL EXPRESSION - (COUNT^18+LOC)
!
!------------------------------------------------------------------------------------------------------------------
	T1_.STK[0];	!T1_LIST POINTER (COUNT^18+LOC)
	T2_.T1[ELMNT];	!T2_LOC(IDENTIFIER)
	% CHECK TO SEE IF ITS REALLY A VARIABLE  %
	IF  NAMSET( VARIABL1, .T2 )  LSS 0  THEN RETURN .VREG;
	% GENERATE THE ASSIGNMENT NODE %
	MULTIASGN(.T2)	! GIVE IT THE LEFT HAND SIDE
END;



GLOBAL ROUTINE ASSISTA=
BEGIN
	EXTERNAL SAVSPACE %(SIZE,LOC)%,BLDVAR %(VPNT)%,NEWENTRY %()%, ASIPTR,TBLSEARCH %()%,STK,TYPE,SETUSE,NAMSET;
	MAP BASE ASIPTR;REGISTER BASE R1:R2;
!SEMANTIC ANALYSIS BEGINS
	!--------------------------------------------------------------------------------
	!THE CALL TO SYNTAX LEAVES A LIST POINTER ON THE STACK (STK[0]).
	!THE POINTER POINTS TO THE LIST:
	!
	!LABEL (LABELEX^18+LOC) - THE LABEL TO BE ASSIGNED
	!VARIABLESPEC - POINTER TO SCALAR OR ARRAY ELEMENT
	!--------------------------------------------------------------------------------
	R1_.STK[0];	!R1_LIST POINTER
	% SET SETUSE FLAG FOR BLDVAR %
	SETUSE _ SETT;
	IF(STK[2]_R2_BLDVAR(.R1[ELMNT1])) LSS 0 THEN RETURN .VREG;
	% BLDVAR ALLOWS ARRAYS WITHOUT SUBSCRIPTS SO DON'T LET THEM THROUGH HERE %
	IF .R2<LEFT>  EQL  IDENTIFIER
	THEN	IF  .R2[OPRSP1]  EQL   ARRAYNM1
		THEN	RETURN FATLEX  ( R2[IDSYMBOL], ARPLIT<0,0>, E4<0,0> );

	R2[IDATTRIBUT(INASSI)]_1;
	NAME_IDOFSTATEMENT_ASSIDATA;NAME<RIGHT>_SORTAB;R2_NEWENTRY();
	R2[ASILBL]_.R1[ELMNT];R2[ASISYM]_@STK[2];SAVSPACE(.R1<LEFT>,@R1);
	IF .ASIPTR<LEFT> EQL 0 THEN ASIPTR<LEFT>_ASIPTR<RIGHT>_@R2
		ELSE
		BEGIN
			ASIPTR[ASILINK]_@R2;ASIPTR<RIGHT>_@R2
		END;
	.VREG
END;
GLOBAL ROUTINE GOTOSTA=
BEGIN
	EXTERNAL SAVSPACE %(SIZE,LOC)%,TBLSEARCH %()%,NEWENTRY %()%,STK,BLDVAR %(VPNT)%,SETUSE;
	EXTERNAL EXPRTYPER,CNVNODE; !DOES TYPE CONVERSION IF NECESSARY
	MACRO GETLAB =
		INCR LLST FROM @STK[2] TO @STK[2]+.STK[2]<LEFT> DO
		BEGIN
			MAP BASE LLST;
			LLST[ELMNT] _ .(@LLST[ELMNT])<RIGHT>
		END
	$;
	LOCAL BASE T1;  REGISTER BASE R1:T2:R2;
!SEMANTIC ANALYSIS BEGINS
	!---------------------------------------------------------------------------------
	!THE SYNTAX ROUTINE RETURNS A POINTER IN STK[0] TO THE LIST:
	!
	!CHOICE 1 - SIMPLE GOTO
	!	LABEL (LABELEX^18+LOC) 
	!CHOICE 2 - ASSIGNED OR COMPUTED GOTO
	!	CHOICE 1 - ASSIGNED GOTO
	!	COUNT^18+LOC - POINTER TO ASSIGNED VARIABLE AND LABEL LIST
	!	CHOICE 2 - COMPUTED GOTO
	!	COUNT^18+LOC - POINTER TO LABEL LIST AND CONTROL EXPRESSION
	!
	!SEE EXPANSION OF METASYMBOL GOTO FOR COMPLETE EXPANSION
	!---------------------------------------------------------------------------------
	R1_.STK[0];					!R1_LIST POINTER
	IF .R1[ELMNT] EQL  1 THEN			!CHOICE 1 - SIMPLE GOTO
	BEGIN
		NAME_IDOFSTATEMENT_GOTODATA;NAME<RIGHT>_SORTAB;T1_NEWENTRY();
		T1[GOTOLBL]_.R1[ELMNT1];T1[GOTONUM]_T1[GOTOLIST]_0;
		RETURN
	END;
	!------------------------------------------------------------------------------
	!AT THIS POINT WE HAVE EITHER A COMPUTED OR ASSIGNED GOTO.
	!R1[ELMNT1] TELLS US WHICH.  CHOICE 1 = ASSIGNED GOTO, 
	!CHOICE 2 = COMPUTED GOTO.
	!------------------------------------------------------------------------------
	R2_.R1[ELMNT2];					!R2_LOC (ASSIGNED OR COMPUTED GOTO COMPONENTS)
	IF .R1[ELMNT1] EQL 1 THEN			!ASSIGNED GOTO
	BEGIN
		SETUSE _ SETT;	! BLDVAR FLAG
		IF (STK[1]_T1_BLDVAR(.R2[ELMNT])) LSS 0 THEN RETURN .VREG;
		% CHECK BLDVAR RETURN FOR UNSUBSCRIPTED ARRAY REFERENCE %
		IF  .T1<LEFT>  EQL  IDENTIFIER
		THEN	IF T1[OPRSP1]  EQL  ARRAYNM1
			THEN  RETURN  FATLEX ( T1[IDSYMBOL], ARPLIT, E4<0,0> ) ;

		IF .R2[ELMNT1] NEQ 0 THEN		!ASSIGNED GOTO WITH LABEL LIST
		BEGIN
			T1_.R2[ELMNT2];STK[2]_.T1[ELMNT1];  !SKIP OPTIONAL COMMA
			GETLAB;
			SAVSPACE(.R2[ELMNT2]<LEFT>,.R2[ELMNT2]);
			STK[2]<LEFT> _ .STK[2]<LEFT>+1;  !INCREMENT COUNT OF LABELS
		END
		ELSE STK[2]_0;NAME_IDOFSTATEMENT_AGODATA;
	END
	ELSE
	BEGIN					!COMPUTED GOTO
		STK[2]_.R2[ELMNT];
		GETLAB;
		T2 _ STK[1] _.R2[ELMNT2];			!SKIP OPTIONAL COMMA
		STK[2]<LEFT> _ .STK[2]<LEFT>+1;  !INCREMENT COUNT OF LABELS
		IF .T2[VALTYPE] NEQ INTEGER THEN  STK[1] _ CNVNODE(.T2,INTEGER,0);
		NAME_IDOFSTATEMENT_CGODATA;
	END;
	SAVSPACE(.R1<LEFT>,@R1);
	NAME<RIGHT>_SORTAB;T1_NEWENTRY();
	!PTR TO LABEL		NUM OF LABELS INLIST	 PTR TO LIST
	T1[GOTOLBL]_.STK[1];T1[GOTONUM]_.STK[2]<LEFT>;T1[GOTOLIST]_.STK[2]<RIGHT>;
	T2_.T1[GOTOLBL]; IF .T2[OPRCLS] NEQ DATAOPR THEN T2[PARENT] _ .T1;
	.VREG
END;


GLOBAL ROUTINE CALLSTA=
BEGIN
	REGISTER T2=2;
	REGISTER BASE T1; MAP BASE T2;REGISTER BASE R1:R2;
	EXTERNAL E121;
	EXTERNAL STK,SAVSPACE %(SIZE,LOC)%,CORMAN %()%,NEWENTRY %()%,TBLSEARCH %()%,NAMSET,NAMREF,NAMDEF;
	MACRO
	CARGPTR=0,0,RIGHT$,CAFLGFLD=0,0,LEFT$,
	ERR15(X) = RETURN FATLEX(X,R2[IDSYMBOL],E15<0,0>)  $;
	MACHOP BLT=#251;
	LOCAL BASE CALLNODE;
!SEMANTIC ANALYSIS BEGINS
	!------------------------------------------------------------------------------------------------------------
	!THIS ROUTINE EXPECTS TO RETURN A POINTER IN STK[0] TO A SUBROUTINE NAME OPTIONALLY FOLLOWED BY AN
	!ARGUMENT LIST. SEE EXPANSION OF METASYMBOL CALL FOR DETAILS.
	!------------------------------------------------------------------------------------------------------------
	R1_.STK[0];
	R2_.R1[ELMNT];	!R2_LOC(SUBROUTINE NAME)
	% DEFINE AND CHECK THE FUNCTION NAME %
	IF NAMREF( FNNAME1 , .R2 )  LSS 0  THEN RETURN .VREG;
	IF .R2[IDATTRIBUT(SFN)]   THEN RETURN  FATLERR(.ISN,E121<0,0>);
	STK[1]_.R2;
!
!MAKE A CALL STATEMENT NODE
!
	NAME_IDOFSTATEMENT_CALLDATA;NAME<RIGHT>_SORTAB;CALLNODE _NEWENTRY();
	IF .R1[ELMNT1] NEQ 0 THEN	!ARGUMENT LIST
	BEGIN
		R2_STK[4]<0,0>;[email protected][ELMNT2];
		INCR ARG FROM @T1 TO @T1+.T1<LEFT> BY 2  DO
		BEGIN
			MAP BASE ARG:R2;
			T2_.ARG[ELMNT1];
			R2[CAFLGFLD]_0;R2[CARGPTR]_.T2;
			IF .ARG[ELMNT] EQL 1 THEN	!EXPRESSION
			BEGIN
				IF .T2[OPRCLS] EQL DATAOPR 
				THEN (R2[P1AVALFLG]_1;
					IF .T2[OPRSP1] EQL  ARRAYNM1
						OR  .T2[OPRSP1]  EQL  VARIABL1
					THEN	NAMSET(VARYREF, .T2 )
					) 
				 ELSE
				 BEGIN
					 T2[PARENT] _ .CALLNODE;
					 IF .T2[OPRCLS] EQL  ARRAYREF
					 THEN  NAMSET( ARRAYNM1, .T2[ARG1PTR])
				 END;

			END
			ELSE	!STATEMENT NUMBER
			BEGIN
				R2[P1AVALFLG]_1;
			END;R2_.R2+1;
		END;[email protected][ELMNT2];SAVSPACE(.T1<LEFT>,.T1); SAVSPACE(0,.R1[ELMNT2]);
		STK[3]_.R2-STK[4]; STK[3]<LEFT> _ 0;
		NAME<LEFT>_.STK[3]+2; R2_CORMAN();
		T1<LEFT>_STK[3];T1<RIGHT>_@R2+1;T2_@R2+1+.STK[3];BLT(T1,0,T2);
	END ELSE R2_0;
	CALLNODE[CALSYM]_.STK[1];CALLNODE[CALLIST]_.R2;
	FLGREG<BTTMSTFL>_0;
	SAVSPACE(.R1<LEFT>,@R1);
	.VREG
END;


GLOBAL ROUTINE RETUSTA=
BEGIN
	REGISTER BASE T1:R2;
	EXTERNAL STK,EXPRTYPER,SAVSPACE %(SIZE,LOC)%,NEWENTRY %()%;
	EXTERNAL LSAVE,LEXL,LEXNAME,EXPRESS,CNVNODE;
	LEXL_LEXEMEGEN(); LSAVE _ -1;
	IF .LEXL<LEFT> NEQ LINEND 
	THEN
	BEGIN
		IF ( STK[0] _ EXPRESS() ) LSS 0
		THEN  RETURN  .VREG;
		IF .LEXL<LEFT>  NEQ  EOSLEX
		THEN	RETURN NOEOSERRL
	END
	ELSE STK[0] _ 0;
!SEMANTIC ANALYSIS BEGINS
	!-----------------------------------------------------------------------------------------------------------
	!THIS ROUTINE EXPECTS IN STK[0], A POINTER TO AN OPTIONAL RETURN EXPRESSION OR 0.
	!-----------------------------------------------------------------------------------------------------------
	NAME_IDOFSTATEMENT_RETUDATA;NAME<RIGHT>_SORTAB;R2_NEWENTRY();
	R2[RETEXPR]_T1_.STK[0];
	IF .T1 NEQ 0
	  THEN (IF .T1[OPRCLS] NEQ DATAOPR THEN T1[PARENT] _ .R2;
		IF .T1[VALTYPE] NEQ INTEGER THEN R2[RETEXPR] _ CNVNODE(.T1,INTEGER,0);
		);
	.VREG
END;
GLOBAL ROUTINE CONTSTA=
BEGIN
	EXTERNAL NEWENTRY;
        IF LEXEMEGEN() NEQ LINEND^18 THEN  RETURN  NOEOSERRV;
!SEMANTIC ANALYSIS BEGINS
	NAME _ IDOFSTATEMENT _ CONTDATA; NAME<RIGHT>_SORTAB; NEWENTRY();
	.VREG
END;
GLOBAL ROUTINE LITOROCT=
BEGIN
!
!PARSES OPTIONAL [LITERAL OR OCTAL STRING ] AFTER STOP OR  PAUSE
!RETURNS LEXEME FOR EITHER
!

	REGISTER R2;
	EXTERNAL  GSTOPOBJ,STLEXEME,LEXICAL;

	IF ( R2_LEXICAL( .GSTOPOBJ ))  EQL  0 
	THEN
	BEGIN	% ITS NOT A DIGIT OR '  %
		IF  LEXICAL (.GSTLEXEME )  NEQ  EOSLEX^18
		THEN
		BEGIN	% AND ITS NOT ENDOF STATEMENT EITHER %
			RETURN FATLEX( PLIT'OCTAL DIGIT STRING OR ''TEXT''?0',LEXPLITV,E0<0,0>)
		END
		% ELSE EOS IS OK %
	END
	ELSE
	BEGIN	% MAKE SURE THAT THERE WERE NO ERRORS IN THE OBJECT %
		IF .R2  EQL  EOSLEX^18
		THEN	RETURN -1;	! SOME SORT OF ERROR OCCURED
		%OTHERWISE ITS AN OCTAL OR LITERAL
		  WHICH MUST BE FOLLOWED BY EOS %
		IF LEXICAL(.GSTLEXEME)  NEQ  EOSLEX^18
		THEN	RETURN NOEOSERRV
	END;

	RETURN .R2
END;	% LITOROCT %



GLOBAL ROUTINE STOPSTA=
BEGIN
	REGISTER BASE R1:R2;
	EXTERNAL STK,SAVSPACE %(SIZE,LOC)%,NEWENTRY %()%,LITOROCT;
	IF (R2 _ LITOROCT()) LSS 0 THEN RETURN -1;
	NAME_IDOFSTATEMENT_STOPDATA;NAME<RIGHT>_SORTAB;R1_NEWENTRY();
	R1[STOPIDENT]_@R2;
	.VREG
END;
GLOBAL ROUTINE PAUSSTA=
BEGIN
	REGISTER BASE R1:R2;
	EXTERNAL STK,SAVSPACE %(SIZE,LOC)%,NEWENTRY %()%,LITOROCT;
	IF (R2 _ LITOROCT()) LSS 0 THEN RETURN -1;
	NAME_IDOFSTATEMENT_PAUSDATA;NAME<RIGHT>_SORTAB;R1_NEWENTRY();
	R1[PAUSIDENT]_.R2;
	.VREG
END;
GLOBAL ROUTINE RWBLD(NODEDATA)=
BEGIN
	REGISTER BASE T1;REGISTER BASE R1:R2;
	EXTERNAL STK,SAVSPACE %(SIZE,LOC)%,BLDUNIT %(VPNT)%,BLDFORMAT %(FPNT)%,
		 IODOXPN,DATALIST %(LPNT)%,TYPE,CORMAN %()%,NEWENTRY %()%;
	LOCAL U,R,F,ER,EN;
	MAP BASE U;
%
	ROUTINE BUILDS A READ OR WRITE STATEMENT NODE 
	CALLED FROM READST OR WRITST WITH READ OR WRITE DATA
	DOESN'T RETURN ANYTHING SIGNIFICANT EXCEPT WHEN ERROR CONDITION
	THEN RETURNS -1
%
	!----------------------------------------------------------------------------------------------------------
	!THIS ROUTINE EXPECTS SYNTAX TO RETURN A POINTER IN STK[0] TO A
	!FULL UNIT SPECIFICATION (UNIT, RECORD NUMBER, FORMAT, END AND ERR) OR
	!A FORMAT SPECIFICATION (FORMAT, END AND ERR) FOLLOWED BY AN OPTIONAL
	!IO LIST.  SEE EXPANSIONS OF THE METASYMBOLS READSPEC, IOSPEC,
	!FORMAT ID AND DATAITEM FOR DETAILS.
	!----------------------------------------------------------------------------------------------------------
	R1_.STK[0];
	IF .R1[ELMNT] EQL 1 THEN !FULL UNIT SPECIFICATION
	BEGIN
		IF BLDUNIT(.R1[ELMNT1]) LSS 0 THEN RETURN .VREG;
	END
	ELSE !FORMAT SPECIFICATION
	BEGIN
		STK[4]_0;STK[5]_STK[6]_0; !SET FORMAT,END,ERR TO ZERO
		R1 _.R1+1; !SET PTR TO POINT TO FORMATSPEC EXPECTED BY BLDFORMAT IN ACT1
		FLAG _ -1;	!SIGNAL BLDFORMAT NOT TO EXPECT AN END= OR ERR=
		IF BLDFORMAT (.R1) LSS 0 THEN RETURN .VREG;
		STK[2]_ IF .NODEDATA EQL READDATA THEN MAKECNST(INTEGER,0,-5) ELSE MAKECNST(INTEGER,0,-3); !READID OR PRINT ID
		 STK[3]_0;!CLEAR RECORD, INDICATE READ FROM STANDARD DEVICE
	END;
	IF .STK[3] NEQ 0
	THEN
	BEGIN
		EXTERNAL FATLEX,E101;
		[email protected][3];
		%LETS NOT HAVE ANY LIST DIRECTED RANDOM ACCESS%
		IF .STK[4] EQL -1
		THEN	FATLEX( PLIT'RANDOM ACCESS?0',E101<0,0>)
	END
	ELSE R _ 0;
	U_.STK[2];F_.STK[4];ER_.STK[5];EN_.STK[6];
	IF .R1[ELMNT2] NEQ 0 THEN	!IO LIST
	BEGIN
	!**;[336],RWBLD @3802, DCE, 09-DEC-75
	![336], TEST FOR NAMELIST I/O - IT IS ILLEGAL WITH I/O LIST!
%[336]%		EXTERNAL FATLEX,E102;
%[336]%		REGISTER BASE SNAME;
%[336]%		SNAME_.F;
%[336]%		IF .SNAME NEQ -1 THEN
%[336]%			IF .SNAME[IDATTRIBUT(NAMNAM)] EQL 1
%[336]%			 THEN FATLEX(E102<0,0>);
		R2_.R1[ELMNT3]; SAVSPACE(.R1[ELMNT3]<LEFT>,.R1[ELMNT3]);
		IF (R2 _ DATALIST(.R2[ELMNT1])) LSS 0 THEN RETURN .VREG;
	END
	ELSE
	BEGIN	%NO IOLIST%
		IF .F EQL  -1  THEN  RETURN FATLEX(E96<0,0>);
			% LIST DIRECTED WITH NO IOLIST%
		R2_0;
	END;

	NAME _IDOFSTATEMENT_.NODEDATA;NAME<RIGHT>_SORTAB;T1_NEWENTRY();
	T1[IOUNIT]_.U;T1[IOFORM]_.F;T1[IORECORD]_.R;T1[IOLIST]_.R2<LEFT>;
	T1[IOERR]_.ER;T1[IOEND]_.EN;
	IODOXPN(.T1);	!DO DOXPN FOR IOLIST
	IF .U[CONST2] LSS 0 THEN R1 _ .R1-1; !UNDO INCREMENT IF FORMAT WITHOUT A UNIT
	SAVSPACE(.R1<LEFT>,@R1);
	.VREG
END;


GLOBAL ROUTINE READSTA=
BEGIN
!SEMANTIC ANALYSIS BEGINS
!
	TYPE _ READD;	!FLAG FOR DATALIST
	RWBLD(READDATA);	!BUILD READ/WRITE NODE
	.VREG
END;
GLOBAL ROUTINE ACCESTA=
BEGIN
	REGISTER BASE T1;
	EXTERNAL BLDIO1;
	T1 _ BLDIO1(READDATA);	!BUILD A READ NODE
	T1[IOUNIT] _ MAKECNST(INTEGER,0,-4);	!ACCEPT ID
	.VREG
END;
GLOBAL ROUTINE PUNCSTA=
BEGIN
	REGISTER BASE T1;
	EXTERNAL BLDIO1;
	T1 _ BLDIO1(WRITDATA);	!BUILD A WRITE (PUNCH) NODE
	T1[IOUNIT] _ MAKECNST(INTEGER,0,-2);	!PUNCH PAPER TAPE ID
	.VREG
END;
GLOBAL ROUTINE WRITSTA=
BEGIN
!SEMANTIC ANALYSIS BEGINS
	TYPE _ WRITEE;	! FLAG FOR DATALIST
	RWBLD(WRITDATA);	!BUILD A WRITE IO STATEMENT NODE
	.VREG
END;
END
ELUDOM