(******************************************************************)
     (*                                                                *)
     (*  Copyright (c) 1978 Regents of the University of California.   *)
     (*  Permission to copy or distribute this software or documen-    *)
     (*  tation in hard or soft copy granted only by written license   *)
     (*  obtained from the Institute for Information Systems.          *)
     (*                                                                *)
     (******************************************************************)

 SEGMENT PROCEDURE USERPROGRAM(INPUT,OUTPUT: FIBP);
 BEGIN FWRITELN(SYSTERM^);
   PL := 'No user program';
   FWRITESTRING(SYSTERM^,PL,0)
 END (*USERPROGRAM*) ;

 SEGMENT PROCEDURE DEBUGGER;
 BEGIN FWRITELN(SYSTERM^);
   PL := 'No debugger in system';
   FWRITESTRING(SYSTERM^,PL,0)
 END (*DEBUGGER*) ;

 SEGMENT PROCEDURE PRINTERROR(XEQERR,IORSLT: INTEGER);
   VAR S: STRING[40];
 BEGIN S := 'Unknown run-time error';
   CASE XEQERR OF
     1:  S := 'Value range error';
     2:  S := 'No proc in seg-table';
     3:  S := 'Exit from uncalled proc';
     4:  S := 'Stack overflow';
     5:  S := 'Integer overflow';
     6:  S := 'Divide by zero';
     7:  S := 'NIL pointer reference';
     8:  S := 'Program interrupted by user';
     9:  S := 'System IO error';
    10:  BEGIN S := 'unknown cause';
           CASE IORSLT OF
             1:  S := 'parity (CRC)';
             2:  S := 'illegal unit #';
             3:  S := 'illegal IO request';
             4:  S := 'data-com timeout';
             5:  S := 'vol went off-line';
             6:  S := 'file lost in dir';
             7:  S := 'bad file name';
             8:  S := 'no room on vol';
             9:  S := 'vol not found';
            10:  S := 'file not found';
            11:  S := 'dup dir entry';
            12:  S := 'file already open';
            13:  S := 'file not open';
            14:  S := 'bad input format'
           END (*IO ERRORS*) ;
         INSERT('IO error: ',S,1)
       END;
    11:  S := 'Unimplemented instruction';
    12:  S := 'Floating point error';
    13:  S := 'String overflow';
    14:  S := 'Programmed HALT';
    15:  S := 'Programmed break-point'
   END (*XEQ ERRORS*) ;

   WRITELN(OUTPUT,S);
   WITH SYSCOM^.BOMBP^ DO
     WRITE(OUTPUT,'S# ',MSSEG^[0] MOD 256,
                  ', P# ',MSJTAB^[0] MOD 256,
                  ', I# ',MSIPC-(ORD(MSJTAB)-2-MSJTAB^[-1]))
 END (*PRINTERROR*) ;

 SEGMENT PROCEDURE INITIALIZE;
   VAR DOTRITON,JUSTBOOTED: BOOLEAN; LTITLE: STRING[40];
       MONTHS: ARRAY [0..15] OF STRING[3];
       DISPLAY: ARRAY [0..79,0..19] OF INTEGER; (*FOR TRITON*)
       STKFILL: ARRAY [0..1199] OF INTEGER;

   PROCEDURE INITSYSCOM;
     VAR TITLE: STRING;
         F: FILE OF MISCINFOREC;
     BEGIN
      (* FIRST SOME GLOBALS *)
         FILLER[0] := CHR(SYSCOM^.CRTCTRL.FILLCOUNT);
         FILLCHAR( FILLER[1], SYSCOM^.CRTCTRL.FILLCOUNT, CHR(0) );
       DEBUGINFO := NIL;
       IPOT[0] := 1; IPOT[1] := 10; IPOT[2] := 100;
       IPOT[3] := 1000; IPOT[4] := 10000; DIGITS := ['0'..'9'];
       WITH SYSCOM^ DO
         BEGIN
         XEQERR := 0;    IORSLT := INOERROR;
         BUGSTATE :=0
         END;
       TITLE := '*SYSTEM.MISCINFO' ;
       RESET( F, TITLE );
       IF IORESULT = ORD(INOERROR) THEN
         BEGIN
         IF NOT EOF( F ) THEN
           WITH SYSCOM^, F^ DO
             BEGIN
             MISCINFO := MSYSCOM.MISCINFO;
             CRTTYPE := MSYSCOM.CRTTYPE;
             CRTCTRL := MSYSCOM.CRTCTRL;
             CRTINFO := MSYSCOM.CRTINFO;
             FILLER[0] := CHR(SYSCOM^.CRTCTRL.FILLCOUNT);
             FILLCHAR( FILLER[1], SYSCOM^.CRTCTRL.FILLCOUNT, CHR(0) );
             END;
         CLOSE( F, NORMAL )
         END;
       UNITCLEAR(1) (*GIVE BIOS NEW SOFT CHARACTERS FOR CONSOLE*)
     END (*INITSYSCOM*) ;

   PROCEDURE INITUNITABLE;
     VAR LUNIT: UNITNUM; LDIR: DIRP;
   BEGIN
     FOR LUNIT := 0 TO MAXUNIT DO
       WITH UNITABLE[LUNIT] DO
         BEGIN UVID := '';
           UISBLKD := LUNIT IN [4,5,9..12];
           IF UISBLKD THEN UEOVBLK := MMAXINT;
           UNITCLEAR(LUNIT);
         END;
     UNITABLE[1].UVID := 'CONSOLE';
     UNITABLE[2].UVID := 'SYSTERM';
     SYVID := '';
     LUNIT := VOLSEARCH(SYVID,TRUE,LDIR);
     SYVID := UNITABLE[SYSCOM^.SYSUNIT].UVID;
     IF LENGTH(SYVID) = 0 THEN HALT;
     IF JUSTBOOTED THEN DKVID := SYVID;
     LUNIT := VOLSEARCH(SYVID,FALSE,LDIR);
     IF LDIR = NIL THEN HALT;
     THEDATE := LDIR^[0].DLASTBOOT;
     UNITCLEAR(6);
     IF IORESULT = ORD(INOERROR) THEN
       UNITABLE[6].UVID := 'PRINTER';
     UNITCLEAR(8);
     IF IORESULT = ORD(INOERROR) THEN
       UNITABLE[8].UVID := 'REMOTE';
   END (*INITUNITABLE*) ;

   PROCEDURE INITFNAMES;
     VAR F: SYSFILE;
         ALLOFEM, FOUND: SET OF SYSFILE;
         LUNIT: UNITNUM;
         LFIB: FIB;
   BEGIN
     FILENAME[ASSMBLER] := 'ASSMBLER';
     FILENAME[COMPILER] := 'COMPILER';
     FILENAME[EDITOR] := 'EDITOR';
     FILENAME[FILER] := 'FILER';
     FILENAME[LINKER] := 'LINKER';
     FINIT(LFIB, NIL,-1);
     FOUND := [];
     FOR F := ASSMBLER TO LINKER DO
       BEGIN
         INSERT(':SYSTEM.', FILENAME[F], 1);
         LTITLE := CONCAT(SYVID,FILENAME[F]);
         FOPEN(LFIB, LTITLE, TRUE, NIL);
         IF LFIB.FISOPEN THEN
           BEGIN
             FILENAME[F] := LTITLE;
             FOUND := FOUND + [F]
           END;
         FCLOSE(LFIB, CNORMAL)
       END;
     LUNIT := 1;
     ALLOFEM := [ASSMBLER,COMPILER,EDITOR,FILER,LINKER];
     WHILE FOUND <> ALLOFEM DO
       BEGIN
         WITH UNITABLE[LUNIT] DO
           IF UISBLKD THEN
             IF UVID <> '' THEN
               FOR F := ASSMBLER TO LINKER DO
                 IF NOT (F IN FOUND) THEN
                   BEGIN
                     LTITLE := CONCAT(UVID, FILENAME[F]);
                     FOPEN(LFIB,LTITLE,TRUE,NIL);

                     IF LFIB.FISOPEN THEN
                       BEGIN
                         FILENAME[F] := LTITLE;
                         FOUND := FOUND + [F]
                       END;
                     FCLOSE(LFIB, CNORMAL)
                   END;
         IF LUNIT = MAXUNIT THEN
           FOUND := ALLOFEM
         ELSE
           LUNIT := LUNIT+1
       END { WHILE }
   END (*INITFNAMES*) ;

   PROCEDURE INITCHARSET;
   TYPE CHARSET= ARRAY [32..127] OF
                   PACKED ARRAY [0..9] OF 0..255;
   VAR I: INTEGER;
       TRIX: RECORD CASE BOOLEAN OF
               TRUE:  (CHARADDR: INTEGER);
               FALSE: (CHARBUFP: ^ CHAR)
             END;
       CHARBUF: RECORD
                    SET1: CHARSET;
                    FILLER1: PACKED ARRAY [0..63] OF CHAR;
                    SET2: CHARSET;
                    FILLER2: PACKED ARRAY [0..63] OF CHAR;
                    TRITON: ARRAY [0..63,0..3] OF INTEGER
                  END (*CHARBUF*) ;
       LFIB: FIB;
   BEGIN FINIT(LFIB,NIL,-1);
     LTITLE := '*SYSTEM.CHARSET';
     FOPEN(LFIB,LTITLE,TRUE,NIL);
     IF LFIB.FISOPEN THEN
       BEGIN UNITWRITE(3,TRIX,128);
         IF IORESULT = ORD(INOERROR) THEN
           BEGIN
             WITH LFIB.FHEADER DO
               BEGIN DOTRITON := DLASTBLK-DFIRSTBLK > 4;
                 UNITREAD(LFIB.FUNIT,CHARBUF,SIZEOF(CHARBUF),DFIRSTBLK)
               END;
             TRIX.CHARADDR := 512-8192;  (*UNIBUS TRICKYNESS!*)
             FOR I := 32 TO 127 DO
               BEGIN
                 MOVERIGHT(CHARBUF.SET1[I],TRIX.CHARBUFP^,10);
                 TRIX.CHARADDR := TRIX.CHARADDR+16
               END;
             TRIX.CHARADDR := 512-6144;
             FOR I := 32 TO 127 DO
               BEGIN
                 MOVERIGHT(CHARBUF.SET2[I],TRIX.CHARBUFP^,10);
                 TRIX.CHARADDR := TRIX.CHARADDR+16
               END;
             UNITABLE[3].UVID := 'GRAPHIC';
             UNITWRITE(3,I,0)
           END
       END
     ELSE
       SYSCOM^.MISCINFO.HAS8510A := FALSE;
     IF DOTRITON THEN
       BEGIN (*INITIALIZE DISPLAY ARRAY*)
         FILLCHAR(DISPLAY,SIZEOF(DISPLAY),0);
         FOR I := 0 TO 63 DO
           MOVELEFT(CHARBUF.TRITON[I],DISPLAY[I,10],8)
       END;
     FCLOSE(LFIB,CNORMAL)
   END (*INITCHARSET*) ;

   PROCEDURE INITHEAP;
   VAR LWINDOW: WINDOWP;
   BEGIN (*BASIC FILE AND HEAP SETTUP*)
     SYSCOM^.GDIRP := NIL; (* MUST PRECEDE THE FIRST "NEW" EXECUTED *)
     NEW(SWAPFIB,TRUE,FALSE); FINIT(SWAPFIB^,NIL,-1);
     NEW(INPUTFIB,TRUE,FALSE);  NEW(LWINDOW);
     FINIT(INPUTFIB^,LWINDOW,0);
     NEW(OUTPUTFIB,TRUE,FALSE);  NEW(LWINDOW);
     FINIT(OUTPUTFIB^,LWINDOW,0);
     NEW(SYSTERM,TRUE,FALSE);  NEW(LWINDOW);
     FINIT(SYSTERM^,LWINDOW,0);
     GFILES[0] := INPUTFIB; GFILES[1] := OUTPUTFIB;
     WITH USERINFO DO
       BEGIN
         NEW(SYMFIBP,TRUE,FALSE); FINIT(SYMFIBP^,NIL,-1);
         NEW(CODEFIBP,TRUE,FALSE); FINIT(CODEFIBP^,NIL,-1)
       END;
     MARK(EMPTYHEAP)
   END (*INITHEAP*) ;

   PROCEDURE INITWORKFILE;
   BEGIN
     WITH USERINFO DO
       BEGIN (*INITIALIZE WORK FILES ETC*)
         ERRNUM := 0; ERRBLK := 0; ERRSYM := 0;
         IF JUSTBOOTED THEN
           BEGIN
             SYMTID := ''; CODETID := ''; WORKTID := '';
             SYMVID := SYVID; CODEVID := SYVID; WORKVID := SYVID
           END;
         IF LENGTH(SYMTID) > 0 THEN
           LTITLE := CONCAT(SYMVID,':',SYMTID)
         ELSE
           LTITLE := '*SYSTEM.WRK.TEXT';
         FOPEN(SYMFIBP^,LTITLE,TRUE,NIL);
         GOTSYM := SYMFIBP^.FISOPEN;
         IF GOTSYM THEN
           BEGIN SYMVID := SYMFIBP^.FVID;
             SYMTID := SYMFIBP^.FHEADER.DTID
           END;
         FCLOSE(SYMFIBP^,CNORMAL);
         IF LENGTH(CODETID) > 0 THEN
           LTITLE := CONCAT(CODEVID,':',CODETID)
         ELSE
           LTITLE := '*SYSTEM.WRK.CODE';
         FOPEN(CODEFIBP^,LTITLE,TRUE,NIL);
         GOTCODE := CODEFIBP^.FISOPEN;
         IF GOTCODE THEN
           BEGIN CODEVID := CODEFIBP^.FVID;
             CODETID := CODEFIBP^.FHEADER.DTID
           END;
         FCLOSE(CODEFIBP^,CNORMAL);
         ALTMODE := SYSCOM^.CRTINFO.ALTMODE;
         SLOWTERM := SYSCOM^.MISCINFO.SLOWTERM;
         STUPID := SYSCOM^.MISCINFO.STUPID
       END
   END (*INITWORKFILE*) ;

 PROCEDURE INITFILES;
   BEGIN
     FCLOSE(SWAPFIB^,CNORMAL);
     FCLOSE(USERINFO.SYMFIBP^,CNORMAL);
     FCLOSE(USERINFO.CODEFIBP^,CNORMAL);
     FCLOSE(INPUTFIB^,CNORMAL);
     FCLOSE(OUTPUTFIB^,CNORMAL);
     LTITLE := 'CONSOLE:';
     FOPEN(INPUTFIB^,LTITLE,TRUE,NIL);
     FOPEN(OUTPUTFIB^,LTITLE,TRUE,NIL);
     IF JUSTBOOTED THEN
       BEGIN LTITLE := 'SYSTERM:';
         FOPEN(SYSTERM^,LTITLE,TRUE,NIL)
       END;
     GFILES[0] := INPUTFIB;
     GFILES[1] := OUTPUTFIB;
     GFILES[2] := SYSTERM;
     GFILES[3] := NIL; GFILES[4] := NIL; GFILES[5] := NIL;
   END (*INITFILES*) ;

 BEGIN (*INITIALIZE*)
   JUSTBOOTED := EMPTYHEAP = NIL;
   DOTRITON := FALSE;
   MONTHS[ 0] := '???'; MONTHS[ 1] := 'Jan';
   MONTHS[ 2] := 'Feb'; MONTHS[ 3] := 'Mar';
   MONTHS[ 4] := 'Apr'; MONTHS[ 5] := 'May';
   MONTHS[ 6] := 'Jun'; MONTHS[ 7] := 'Jul';
   MONTHS[ 8] := 'Aug'; MONTHS[ 9] := 'Sep';
   MONTHS[10] := 'Oct'; MONTHS[11] := 'Nov';
   MONTHS[12] := 'Dec'; MONTHS[13] := '???';
   MONTHS[14] := '???'; MONTHS[15] := '???';
   IF JUSTBOOTED THEN INITHEAP
   ELSE RELEASE(EMPTYHEAP);
   INITUNITABLE; (*AND THEDATE*)
   INITFNAMES;
   INITFILES;
   INITWORKFILE;
   IF SYSCOM^.MISCINFO.HAS8510A THEN
     INITCHARSET;
   INITSYSCOM; (*AND SOME GLOBALS*)
   CLEARSCREEN; WRITELN(OUTPUT);
   IF JUSTBOOTED THEN
     BEGIN
       IF DOTRITON THEN
         BEGIN (*ASSUME DATA MEDIA SCREEN*)
           WRITE(OUTPUT,CHR(30),CHR(32),CHR(41));
           UNITWRITE(3,DISPLAY[-80],23)
         END;
       WRITELN(OUTPUT,'Welcome  ',SYVID,',  to');
       IF DOTRITON THEN WRITELN(OUTPUT);
       WRITELN(OUTPUT,'U.C.S.D.  Pascal  System  I.5');
       IF DOTRITON THEN WRITELN(OUTPUT);
       WITH THEDATE DO
         WRITE(OUTPUT,'Current date is  ',DAY,'-',MONTHS[MONTH],'-',YEAR)
     END
   ELSE
     WRITE(OUTPUT,'System re-initialized')
 END (*INITIALIZE*) ;

 SEGMENT FUNCTION GETCMD(LASTST: CMDSTATE): CMDSTATE;
   CONST ASSEMONLY = LINKANDGO;
   VAR CH: CHAR; BADCMD: BOOLEAN;

   PROCEDURE RUNWORKFILE(OKTOLINK, RUNONLY: BOOLEAN);
     FORWARD;

   FUNCTION ASSOCIATE(TITLE: STRING; OKTOLINK, RUNONLY: BOOLEAN): BOOLEAN;
     LABEL 1;
     VAR RSLT: IORSLTWD; LSEG: SEGRANGE;
         SEGTBL: RECORD
                   DISKINFO: ARRAY [SEGRANGE] OF SEGDESC;
                   SEGNAME: ARRAY [SEGRANGE] OF
                              PACKED ARRAY [0..7] OF CHAR;
                   SEGKIND: ARRAY [SEGRANGE] OF
                              (LINKED,HOSTSEG,SEGPROC,UNITSEG,SEPRTSEG);
                   FILLER: ARRAY [0..143] OF INTEGER
                 END { SEGTBL } ;
   BEGIN ASSOCIATE := FALSE;
     FOPEN(USERINFO.CODEFIBP^,TITLE,TRUE,NIL);
     RSLT := SYSCOM^.IORSLT;
     IF RSLT <> INOERROR THEN
       BEGIN
         IF TITLE <> '*SYSTEM.STARTUP' THEN
           IF RSLT = IBADTITLE THEN
             WRITE(OUTPUT,'Illegal file name')
           ELSE
             WRITE(OUTPUT,'No file ',TITLE);
         GOTO 1
       END;
     WITH USERINFO,SYSCOM^ DO
       IF CODEFIBP^.FHEADER.DFKIND <> CODEFILE THEN
         BEGIN
           WRITE(OUTPUT,TITLE,' not code');
           GOTO 1
         END
       ELSE
         BEGIN
           UNITREAD(CODEFIBP^.FUNIT,SEGTBL,SIZEOF(SEGTBL),
                         CODEFIBP^.FHEADER.DFIRSTBLK);
           IF IORESULT <> ORD(INOERROR) THEN
             BEGIN
               WRITE(OUTPUT,'Bad block #0');
               GOTO 1
             END;
           WITH SEGTBL DO
             FOR LSEG := 0 TO MAXSEG DO
               IF (SEGKIND[LSEG]<LINKED) OR (SEGKIND[LSEG]>SEPRTSEG) THEN
                 BEGIN { PRE I.5 CODE...FIX UP! }
                   FILLCHAR(SEGKIND, SIZEOF(SEGKIND), ORD(LINKED));
                   FILLCHAR(FILLER, SIZEOF(FILLER), 0);
                   UNITWRITE(CODEFIBP^.FUNIT, SEGTBL, SIZEOF(SEGTBL),
                                 CODEFIBP^.FHEADER.DFIRSTBLK)
                 END;
           WITH SEGTBL DO
             FOR LSEG := 0 TO MAXSEG DO
               IF SEGKIND[LSEG] <> LINKED THEN
               BEGIN
                 IF OKTOLINK THEN
                   BEGIN WRITELN(OUTPUT,'Linking...');
                     FCLOSE(CODEFIBP^, CNORMAL);
                     IF ASSOCIATE(FILENAME[LINKER], FALSE, FALSE) THEN
                       BEGIN
                         IF RUNONLY THEN GETCMD := LINKANDGO
                         ELSE GETCMD := LINKDEBUG;
                         EXIT(GETCMD)
                       END
                   END
                 ELSE
                   IF NOT (LASTST IN [LINKANDGO, LINKDEBUG]) THEN
                     WRITE(OUTPUT,'Must L(ink first');
                 GOTO 1
               END;
           FOR LSEG := 1 TO MAXSEG DO
             IF (LSEG = 1) OR (LSEG >= 7) THEN
               WITH SEGTABLE[LSEG],SEGTBL.DISKINFO[LSEG] DO
                 BEGIN CODEUNIT := CODEFIBP^.FUNIT;
                   CODEDESC.CODELENG := CODELENG;
                   CODEDESC.DISKADDR := DISKADDR+
                                         CODEFIBP^.FHEADER.DFIRSTBLK
                 END
         END;
     ASSOCIATE := TRUE;
 1:  FCLOSE(USERINFO.CODEFIBP^,CNORMAL)
   END (*ASSOCIATE*) ;

   PROCEDURE STARTCOMPILE(NEXTST: CMDSTATE);
     LABEL 1;
     VAR TITLE: STRING[40];
   BEGIN
     IF NEXTST = ASSEMONLY THEN
       WRITE(OUTPUT,'Assembling')
     ELSE
       WRITE(OUTPUT,'Compiling');
     WRITELN(OUTPUT,'...');

     IF NEXTST = ASSEMONLY THEN
       TITLE := FILENAME[ASSMBLER]
     ELSE
       TITLE := FILENAME[COMPILER];
     IF ASSOCIATE(TITLE, FALSE, FALSE) THEN
       WITH USERINFO DO
         BEGIN
             IF GOTSYM THEN
               TITLE := CONCAT(SYMVID,':',SYMTID)
             ELSE
               BEGIN
                 IF NEXTST = ASSEMONLY THEN
                   WRITE(OUTPUT, 'Assemble')
                 ELSE
                   WRITE(OUTPUT, 'Compile');
                 WRITE(OUTPUT,' what text? ');
                 READLN(INPUT, TITLE);
                 IF TITLE = '' THEN GOTO 1;
                 INSERT('.TEXT', TITLE, LENGTH(TITLE)+1);
                 GOTCODE := FALSE
               END;
             FOPEN(SYMFIBP^,TITLE,TRUE,NIL);
             IF IORESULT <> ORD(INOERROR) THEN
               BEGIN
                 WRITE(OUTPUT,'Can''t find ', TITLE);
                 GOTSYM := FALSE; GOTO 1
               END;
             TITLE := '*SYSTEM.SWAPDISK';
             FOPEN(SWAPFIB^,TITLE,TRUE,NIL);
             TITLE := '*SYSTEM.WRK.CODE[*]';
             FOPEN(CODEFIBP^,TITLE,FALSE,NIL);
             IF IORESULT <> ORD(INOERROR) THEN
               BEGIN
                 WRITE(OUTPUT,'Code open error!');
                 GOTO 1
               END;
             ERRNUM := 0; ERRBLK := 0; ERRSYM := 0;
             IF NEXTST = ASSEMONLY THEN
               NEXTST := COMPONLY;
             GETCMD := NEXTST; EXIT(GETCMD)
         END;
   1:
   END (*STARTCOMPILE*) ;

   PROCEDURE FINISHCOMPILE;
   BEGIN
     FCLOSE(USERINFO.SYMFIBP^,CNORMAL);
     FCLOSE(SWAPFIB^,CNORMAL);
     IF SYSCOM^.MISCINFO.HAS8510A THEN
       UNITCLEAR(3);
     WITH USERINFO DO
       IF ERRNUM > 0 THEN
         BEGIN GOTCODE := FALSE;
           FCLOSE(CODEFIBP^,CPURGE);
           IF ERRBLK > 0 THEN
             BEGIN CLEARSCREEN; WRITELN(OUTPUT);
               IF ASSOCIATE(FILENAME[EDITOR], FALSE, FALSE) THEN
                 BEGIN GETCMD := SYSPROG; EXIT(GETCMD) END
             END
         END
       ELSE
         BEGIN GOTCODE := TRUE;
           CODEVID := CODEFIBP^.FVID;
           CODETID := CODEFIBP^.FHEADER.DTID;
           FCLOSE(CODEFIBP^,CLOCK);
           IF LASTST IN [COMPANDGO,COMPDEBUG] THEN
             RUNWORKFILE(TRUE, LASTST = COMPANDGO)
         END
   END (*FINISHCOMPILE*) ;

   PROCEDURE EXECUTE;
     VAR TITLE: STRING[255];
   BEGIN
     WRITE(OUTPUT,'Execute');
     IF NOT SYSCOM^.MISCINFO.SLOWTERM THEN
       WRITE(OUTPUT,' what file');
     WRITE(OUTPUT,'? '); READLN(TITLE);
     IF LENGTH(TITLE) > 0 THEN
       BEGIN
         IF TITLE[LENGTH(TITLE)] = '.' THEN
           DELETE(TITLE,LENGTH(TITLE),1)
         ELSE
           INSERT('.CODE',TITLE,LENGTH(TITLE)+1);
         IF ASSOCIATE(TITLE, FALSE, FALSE) THEN
           BEGIN GETCMD := SYSPROG; EXIT(GETCMD) END
       END
   END (*EXECUTE*) ;

   PROCEDURE RUNWORKFILE;
   BEGIN
     WITH USERINFO DO
     IF GOTCODE THEN
       BEGIN CLEARSCREEN;
         IF ASSOCIATE(CONCAT(CODEVID,':',CODETID), OKTOLINK, RUNONLY) THEN
           BEGIN
             WRITELN(OUTPUT,'Running...');
             IF RUNONLY THEN
                 GETCMD := SYSPROG
             ELSE
                 GETCMD := DEBUGCALL;
             EXIT(GETCMD)
           END;
         IF NOT (LASTST IN [LINKANDGO, LINKDEBUG]) THEN
           GOTCODE := FALSE
       END
     ELSE
       IF RUNONLY THEN
         STARTCOMPILE(COMPANDGO)
       ELSE
         STARTCOMPILE(COMPDEBUG)
   END { RUNWORKFILE } ;

 BEGIN (*GETCMD*)
   FRESET(INPUTFIB^); FRESET(OUTPUTFIB^); FRESET(SYSTERM^);
   GFILES[0] := INPUTFIB; GFILES[1] := OUTPUTFIB;
   IF LASTST = HALTINIT THEN
     IF ASSOCIATE('*SYSTEM.STARTUP',FALSE,FALSE) THEN
       BEGIN CLEARSCREEN;
         WRITELN(OUTPUT,'Initializing...');
         GETCMD := SYSPROG; EXIT(GETCMD)
       END;
   IF LASTST IN [COMPONLY,COMPANDGO,COMPDEBUG] THEN
     FINISHCOMPILE;
   IF LASTST IN [LINKANDGO,LINKDEBUG] THEN
     RUNWORKFILE(FALSE, LASTST = LINKANDGO);
   IF SYSCOM^.MISCINFO.USERKIND = AQUIZ THEN
     IF LASTST = HALTINIT THEN
       BEGIN LASTST := COMPANDGO; RUNWORKFILE(TRUE, TRUE) END
     ELSE
       BEGIN
         EMPTYHEAP := NIL;
         GETCMD := HALTINIT;
         EXIT(GETCMD)
       END;
   WITH USERINFO DO
     BEGIN ERRNUM := 0; ERRBLK := 0; ERRSYM := 0 END;
   BADCMD := FALSE;
   REPEAT
     PL :=
 'Command: E(dit, R(un, F(ile, C(omp, L(ink, X(ecute, A(ssem, D(ebug,? [I.5e]';
     PROMPT; CH := GETCHAR(BADCMD); CLEARSCREEN;
     IF CH = '?' THEN
       BEGIN PL := 'Command: U(ser restart, I(nitialize, H(alt';
         PROMPT; CH := GETCHAR(BADCMD); CLEARSCREEN
       END;
     BADCMD := NOT (CH IN ['E','R','F','C','L','X','A','D','U','I','H','?']);
     IF NOT BADCMD THEN
       CASE CH OF
         'E':  BEGIN WRITELN(OUTPUT);
                 IF ASSOCIATE(FILENAME[EDITOR], FALSE, FALSE) THEN
                   BEGIN GETCMD := SYSPROG; EXIT(GETCMD) END
               END;
         'F':  BEGIN WRITELN(OUTPUT);
                 IF ASSOCIATE(FILENAME[FILER], FALSE, FALSE) THEN
                   BEGIN GETCMD := SYSPROG; EXIT(GETCMD) END
               END;
         'L':  BEGIN WRITELN(OUTPUT,'Linking...');
                 IF ASSOCIATE(FILENAME[LINKER], FALSE, FALSE) THEN
                   BEGIN GETCMD := SYSPROG; EXIT(GETCMD) END
               END;
         'X':  EXECUTE;
         'C':  STARTCOMPILE(COMPONLY);
         'A':  STARTCOMPILE(ASSEMONLY);
         'U':  IF LASTST <> UPROGNOU THEN
                 BEGIN
                   WRITELN(OUTPUT,'Restarting...');
                   GETCMD := SYSPROG; EXIT(GETCMD)
                 END
               ELSE
                 BEGIN WRITELN(OUTPUT); WRITE(OUTPUT,'U not allowed') END;
     'R','D':  RUNWORKFILE(TRUE, CH = 'R');
     'I','H':  BEGIN
                 GETCMD := HALTINIT;
                 IF CH = 'H' THEN
                   EMPTYHEAP := NIL;
                 EXIT(GETCMD)
               END
       END
   UNTIL FALSE
 END (*GETCMD*) ;