[pdp8.git] / sw / os8 / v3d / sources / system / dectapes / dectape4 / KL8E.PA

/17 SUPER TTY HANDLER FOR OS/8
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/COPYRIGHT  (C)  1974,1975,1977 BY DIGITAL EQUIPMENT CORPORATION
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/THE INFORMATION IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE
/AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT
/CORPORATION.  DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY
/FOR ANY ERRORS THAT MAY APPEAR IN THIS DOCUMENT.
/
/THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED TO THE PURCHASER
/UNDER A LICENSE FOR USE ON A SINGLE COMPUTER SYSTEM AND CAN BE COPIED
/(WITH INCLUSION OF DIGITAL'S COPYRIGHT NOTICE) ONLY FOR USE IN SUCH
/SYSTEM, EXCEPT AS MAY OTHERWISE BE PROVIDED IN WRITING BY DIGITAL.
/
/DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY FOR THE USE
/OR RELIABILITY OF ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY
/DIGITAL.
/
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/

/S.W.,S.R.,H.J.,R.L.,S.R.

        *0

        -1
        DEVICE KL8E;DEVICE TTY;0;TTY&177+4000;ZBLOCK 2

/TWO-PAGE TELETYPE HANDLER FOR OS/8 V3.
/ON INPUT, RECOGNIZES ^Z, ^C, ^U, RUBOUT
/^Z     MEANS END OF INPUT, INSERT ^Z IN BUFFER,
/       PAD WITH ZEROES, AND ECHO "^Z"
/^C     MEANS ABORT JOB, RETURN TO OS/8 VIA LOC 7600 TO SAVE CORE AND PRINT "^C"
/^U     MEANS DELETE THE LAST LINE, ALLOW OPERATOR TO RETYPE
/       (LINE STARTS AT BEGIN OF BUFFER AND IS TERMINATED BY A CR)
/       A CR GETS ENTERED INTO BUFFER, CAUSES A LF TO ALSO ECHO
/       AND GET ENTERED INTO BUFFER, BUFFER IS THEN PADDED WITH NULLS.
/       CONVERTS LC TO UC

/ON OUTPUT RECOGNIZES ^C, ^O, ^S, ^Q FROM KEYBOARD
/^C     CAUSES JOB TO ABORT, RETURN TO OS/8 VIA LOCATION 7600
/       TO SAVE CORE AND PRINT "^C"
/^O     CAUSES ECHOING BY THE HANDLER TO CEASE
/       TYPING ANY OTHER CHARACTER RESUMES ECHOING.
/^S     CAUSES THE HANDLER TO STOP SENDING TO TERMINAL
/^Q     RESUMES HANDLER SENDING
/       ^S AND ^Q ARE IGNORED  IN OTHER CASES

/WHENEVER PRINTING CHARACTERS (EITHER ON OUTPUT OR WHEN ECHOING),
/       IGNORES NULLS
/       FLAGS LC WITH AN APOSTROPHE
/       HANDLES TABS CORRECTLY (SEVERAL WAYS)
/       PRINTS ESCAPE AS $
/       DELAYS 16 MS AFTER LINEFEEDS
/       PRINTS CONTROL CHARACTERS AS "^K"

/DOES AUTOMATIC CR/LF AT END OF LINE WIDTH.

/MAINTENANCE RELEASE CHANGES:

/1.     ADDED KCC FOR NON-CONSOLE TELETYPES

/V3D CHANGES: (VERSION E)

/1.     ADDED DELAY OPTION FOR VT78
/2.     ADDED SCOPE RUBOUTS
/3.     CHANGED VT78 DEFAULTS
/4.     REARRANGED CODE FOR SET TTY ESC AND ARROW
\f       INDVC=03
        OUTDVC=04

        KSF=10^INDVC+6001
        KCC=10^INDVC+6002
        KRS=10^INDVC+6004
        KRB=KCC KRS
        TSF=10^OUTDVC+6001
        TCF=10^OUTDVC+6002
        TPC=10^OUTDVC+6004
        TLS=TCF TPC

        TTYVERSION="E&77
\f/BUILD YOUR OWN TELETYPE HANDLER:

/THIS SOURCE HAS MUMBLE LOCATIONS LEFT.

/THE FOLLOWING CONDITIONALS ALLOW YOU TO INCLUDE OPTIONAL FEATURES.
/YOU MAY INCLUDE AS MANY OR AS FEW AS YOU DESIRE PROVIDED THERE
/IS ROOM LEFT.

/CONDITIONAL    LOCATIONS       LOCATIONS       INCLUDED
/VARIABLE       PAGE 1          PAGE 2          FEATURES

/ DELAY          0               7              DELAY AFTER GIVEN CHAR
/ CTRL           0               3              PRINT CONTROL CHARS AS ^K
/ RUB            0               0              PRINT CHAR RUBBED OUT ON RUBOUTS
/ SIMTAB         0              10              SIMULATE TABS AS SPACES
/ SLOTAB         0               6              PUT OUT 2 RUBOUTS AFTER A TAB
/ ESC            0              10              PRINT ESCAPE AS $
/ FLAGLC         0              12              FLAG LOWER CASE CHARS ON OUTPUT
/ CNVLC          0               7              CONVERT LOWER CASE ON INPUT TO UPPER CASE
/ ALTMOD         0              11              CONVERT ALTMODES (175,176) TO ESCAPE (33)
/ PAUS           0              20              PAUSE BETWEEN PAGES
/ FREE LOCS:     2              33

        VT78=1          /SET TO 0 TO ALLOW OTHER PARAMETERS
                        /SET TO 1 TO FORCE OTHER PARAMETERS TO VT78 COMPATIBLE

        DELAY=0         /SET NON-ZERO TO ALLOW DELAY AFTER ANY CHAR (12=CR)
                        /TYPICALLY AFTER LF FOR HIGH SPEED VT05
                        /SET VALUE OF DELAY = 7-BIT CHAR TO DELAY AFTER

        CTRL=1          /SET TO 1 TO ECHO CONTROL CHARS AS ^K
                        /SET TO 0 TO ACCEPT CONTROL CHARACTERS AND PUT
                        /IN BUFFER, BUT NOT ECHO THEM (EXCEPT THE USUAL)
        RUB=1           /SET TO 0 TO ECHO EACH RUBOUT BY TYPING A BACK SLASH
                        /SET TO 1 TO ECHO CHARS RUBBED OUT UPON RUB-OUT
                        /SET TO 4000 TO PERFORM SCOPE TYPE RUBOUTS
        SIMTAB=1        /SET TO 1 TO SIMULATE TABS AS THE CORRECT NUMBER OF SPACES
                        /SET TO 0 TO TYPE TABS AS TABS
        SLOTAB=0        /SET TO 1 TO TYPE 2 RUBOUTS AFTER A TAB
                        /ONLY IS APPLICABLE IF SIMTAB=0
        ALTMOD=0        /SET TO 1 TO CONVERT 175,176 TO 33
                        /(UPPER CASE TERMINALS ONLY)
        ESC=1           /SET TO 1 TO ECHO ESCAPE AS $
                        /SET TO 0 TO ECHO ESCAPE AS A CONTROL CHAR (^[)
        FLAGLC=1        /SET TO 1 TO FLAG LOWER CASE CHARS ON OUTPUT
                        /THIS IS FOR PEOPLE NOT PRIVELIDGED ENOUGH TO
                        /OWN A LOWER CASE TERMINAL
                        /SET TO 0 TO PRINT LOWER CASE CHARS AS IS
        CNVLC=0         /SET TO 1 TO CONVERT LOWER CASE CHARS ON INPUT TO UPPER CASE
                        /SET TO 0 TO ACCEPT INPUTTED LOWER CASE CHARS AS IS
                        /THIS IS FOR PEOPLE WHO ARE HANDICAPPED BY A LOWER CASE
                        /TERMINAL AND ONLY WANT UPPER CASE
        PAUS=200        /NON-0 PAUSES BETWEEN SCOPE PAGES
        HEIGHT=30       /NUMBER OF LINES PER SCREEN

/SOME OF THE ABOVE OPTIONS SHOULD ACTUALLY BE IMPLEMENTED
/IN SUCH A MANNER THAT THE USER CAN CHANGE THEM VIA AN ALTER
/RATHER THAN HAVE TO REASSEMBLE.

        IFNZRO VT78 <
        DELAY=0
        CTRL=1
        RUB=4000
        SIMTAB=0
        SLOTAB=0
        ALTMOD=0
        ESC=1
        FLAGLC=0
        CNVLC=0
        IFNZRO INDVC-3 <CTRL=0>
        >
\f/CROSS PAGE LINKAGE:

/THIS CODE MUST BE ABLE TO LOAD INTO ANY TWO PAGES OF CORE
/THE ENTRY POINT IS AT THE NEXT LOCATION TO THE END OF THE FIRST PAGE
/AT THE END OF THE FIRST PAGE WE JMS TO PLINK,
/THIS LEAVES THE ADDRESS OF THE FIRST LOCATION OF THE NEXT PAGE
/IN LOCATION 'PLINK' .  THIS JUST HAPPENS TO BE THE ADDRESS
/OF BOTH TTYPCH AND TTYGCH.

/TTYPCH AND TTYGCH SHARE THE SAME ENTRY POINT.
/IF IT IS CALLED WITH A 0 AC, IT IS A CALL TO TTYGCH,
/IF IT IS CALLED WITH A NON-ZERO AC, IT IS A CALL TO TTYPCH.

/RETURN 1 MEANS GOT RUBOUT
/TTYGCH TAKES RETURN 2 IF IT GOT A ^Z.
/OTHERWISE IT TAKES RETURN 3 WITH CHARACTER GOTTEN IN AC.

/TTYPCH TAKES RETURN 1 IF IT WANTS THE HANDLER TO GO AWAY,
/I.E IF IT SAW A ^Z.
/AC IS NORMALLY NON-ZERO UPON RETURN
/AC IS POSITIVE MEANS DO A CRLF

/WHEN ECHOING WE WANT TO CALL TTYPRT
/BUT OTHERWISE WE WANT TO CALL TTYPCH (WHICH DOES ADDITIONAL
/STUFF LIKE CHECK ^O, ^Q, ETC.
/WE TELL BY WHETHER OR NOT TTYGCH HAD BEEN PREVIOUSLY CALLED.
\f       *200

PLINK,  0               /GETS ADDRESS OF TTYPCH AND TTYGCH (START OF NEXT PAGE)
        STL CLA RAR     /4000
        TAD I TTY       /RETRIEVE FUNCTION WORD, BUT PUT R/W BIT IN LINK
        AND L3700       /EXTRACT NUMBER OF DOUBLE-WORDS TO TRANSFER
        CMA             /GET COUNT+1
        DCA BUFSIZ      /STORE AWAY
        RDF             /FIND OUT THE USER'S DATA FIELD
        TAD CIFCDF      /FORM OUR EXIT CIF CDF
        DCA TTYXIT      /STORE AWAY FOR EXIT ROUTINE
        TAD TTY70       /GET FUNCTION WORD
L776,   AND I TTY       /ISOLATE FIELD OF BUFFER
        TAD TTYCDF      /FORM CDF TO FIELD OF BUFFER
        DCA TTCDBF      /STORE WHERE IT WILL BE USEFUL
                        /AT SAME TIME, INITIALIZE TTYEOF
        ISZ TTY         /POINT TO BUFFER ADDRESS
        TAD I TTY       /AND GET IT
        DCA BUFSTRT     /AND SAVE IT
        ISZ TTY         /POINT TO BLOCK #
TTY376, ISZ TTY         /POINT TO ERROR RETURN
SHIFT,                  /OUTPUT SHIFT REGISTER
TTYEOF,                 /0 IF SAW CR OR ^Z AND WISH TO PAD BUFFER WITH 0'S
TTCDBF, HLT             /CDF BUFFER FIELD
        JMP TTYKLG
TTYLP,  SNL CLA         /LINK=1 MEANS OUTPUT
        JMP TTYGET      /INPUT IS FROM TTY:
\f/LINK MUST BE SET FIRST TIME THROUGH HERE.
/IT ACTS AS A GUARD BIT IN THE SHIFT REGISTER
ROTL,   RTL
        RTL
        SPA             /DO WE HAVE 8 BITS SHIFTED IN?
        JMP TELP
        DCA SHIFT       /SAVE SHIFT REGISTER
        TAD I BUFSTRT
        SZA
        JMS PUNCH       /PRINT A CHARACTER
        TAD I BUFSTRT
        ISZ BUFSTRT     /BUMP INPUT POINTER
TT7400, 7400            /PROTECT ISZ
        AND TT7400
        CLL RAL
        TAD SHIFT       /SHIFT HIGH ORDER 4 BITS INTO
        JMP ROTL        /SHIFT REGISTER
TELP,   JMS PUNCH       /PRINT 3RD CHARACTER OF DOUBLE-WORD
        STL             /***KLUDGE
TTYKLG, ISZ BUFSIZ      /DONE?
        JMP TTYLP       /NOT YET
TTYX,   TAD TTYEOF      /IF INPUT AND WE WERE PADDING WITH 0'S
        SZA CLA         /TAKE SOFT ERROR EXIT
TTYRTN, ISZ TTY         /POINT TO NORMAL RETURN
                        /CAN'T GET ERROR OR END-OF-FILE ON OUTPUT
TTYXIT, HLT             /RETURN TO USER'S FIELD
        JMP I TTY       /RETURN TO USER
TTYCA,  0
TTYWC,  0
BUFSIZ, 0
BUFSTRT,0
TTY70,  70

PUNCH,  0               /NEVER CALL TTYPCH WITH ZERO AC
        JMS I PLINK     /CALL TTYPCH
        JMP TTYRTN      /GO AWAY, WE SAW A ^Z
L7700,  SMA CLA         /DID WE REACH END OF TTY LINE?
        JMS CRLF        /YES, PERFORM CR/LF
        JMP I PUNCH     /RETURN

TMP,
CRLF,   0
        TAD L215
        JMS I PLINK     /CALL TTYPCH TO PRINT CR
L215,   215             /CAN'T RETURN HERE
        CLA             /****
        TAD L212
        JMS I PLINK     /CALL TTYPCH TO PRINT LF
L212,   212             /CAN'T RETURN HERE
        CLA             /****
        JMP I CRLF      /RETURN
\fCTRLU, JMS CRLF        /PERFORM A CR/LF
TTYGET, TAD BUFSTRT
        DCA TTYCA       /POINT TO START OF BUFFER
        TAD BUFSIZ
        CLL RAL         /CONVERT DOUBLE-WORDS TO WORDS
DCAWC,  DCA TTYWC       /SET SIZE OF BUFFER
TSTEND, TAD TTYEOF
        SNA CLA
        JMP ZERO
        JMS I PLINK     /CALL TTYGCH TO GET A CHARACTER
        JMP RUBOUT      /RETURN 1 MEANS SAW RUBOUT
ZERO,   DCA I TTYCA     /RETURN 2 MEANS GOT CHARACTER
                        /STORE AWAY TEMPORARILY
                        /USING USER'S BUFFER AS A TEMP LOCATION
        TAD I TTYCA     /GET BACK CHARACTER
        IFNZRO .-320 <_ERROR>
        SZA
        JMS PUNCH       /ECHO IT
        TAD I TTYCA     /GET IT AGAIN
        TAD M32         /-^Z
        SNA
        JMP CTRLZ
        TAD L5          /^Z-^U
        SNA             /IS IT ^U?
        JMP CTRLU       /YES
        TAD L7
GRUDGE, DCA TMP
        ISZ TTYCA       /NO
L7,     7
        ISZ TTYWC       /IS BUFFER FULL?
TT10,   SKP
        JMP TTYX
        ISZ TMP         /WAS LAST CHAR A CR?
        JMP TSTEND      /NO
        DCA TTYEOF      /YES, SET "PAD WITH 0'S" FLAG
        ISZ TTY         /POINT TO NORMAL RETURN
                        /CR IS NOT AN ERROR OR END-OF-FILE
        TAD L212        /IF LAST CHAR INPUT WAS CR, NOW PRETEND LF WAS INPUT
        JMP ZERO        /REJOIN PROCESSING

CTRLZ,  DCA TTYEOF
        JMS CRLF
        JMP GRUDGE

M32,    -32
L5,     5
L3700,  3700
CIFCDF, CIF CDF 0
TTYCDF, CDF 0

/TTYEOF IS ZERO MEANS PAD BUFFER WITH ZEROES
\f/DON'T DO YET:
/RUBOUT,        AND TTYWC       /177 IN AC
/       SNA CLA
/       JMP CTRLU

RUBOUT, KCC             /TTYGCH DOESN'T CLEAR RO FROM BUFFER
        TAD TTYCA
        CIA
        TAD BUFSTRT
        SNA CLA         /ARE WE AT BEGIN OF BUFFER?
        JMP CTRLU       /YES
        STA
        TAD TTYCA
        DCA TTYCA
        IFZERO RUB <
LSLASH, "\
        TAD LSLASH              /PRINT A BACK SLASH FOR EACH RUBBED OUT CHAR
        >
        IFNZRO RUB&4000+RUB <TAD I TTYCA>       /PRINT CHAR JUST DELETED
        IFNZRO RUB&4000 <TAD TT10>      /BACKSPACE-SPACE-BACKSPACE
        JMS PUNCH
        STA
        TAD TTYWC
        JMP DCAWC       /BUMP BACK WC AND GET ANOTHER CHAR

        ZBLOCK 376-.
TTY,    TTYVERSION      /ENTRY POINT TO HANDLER
        JMS PLINK       /SET UP CROSS PAGE LINKAGE
        IFNZRO TTY-376 <ENTERR,QQQQ>
        PAGE
\f/INTERLUDE:

/USA STANDARD CODE FOR INFORMATION INTERCHANGE:

/       000     001     010     011     100     101     110     111
/
/ 0000  NUL     DLE     SP      0       @       P       '       'P
/
/ 0001  SOH     DC1     !       1       A       Q       'A      'Q
/
/ 0010  STX     DC2     "       2       B       R       'B      'R
/
/ 0011  ETX     DC3     #       3       C       S       'C      'S
/
/ 0100  EOT     DC4     $       4       D       T       'D      'T
/
/ 0101  ENQ     NAK     %       5       E       U       'E      'U
/
/ 0110  ACK     SYN     &       6       F       V       'F      'V
/
/ 0111  BEL     ETB     '       7       G       W       'G      'W
/
/ 1000  BS      CAN     (       8       H       X       'H      'X
/
/ 1001  HT      EM      )       9       I       Y       'I      'Y
/
/ 1010  LF      SUB     *       :       J       Z       'J      'Z
/
/ 1011  VT      ESC     +       ;       K       [       'K      '[
/
/ 1100  FF      FS      ,       <       L       \       'L      '\
/
/ 1101  CR      GS      -       =       M       ]       'M      ']
/
/ 1110  SO      RS      .       >       N       ^       'N      '^
/
/ 1111  SI      US      /       ?       O       _       'O      '_
/
\f/TTYGCH:       GETS A CHAR FROM KBD
/       IF GOT ^Z, IT SETS TTYEOF FLAG
/       LEAVES IT IN AC IN 7-BIT

/TTYPRT:        PRINTS CHAR IN AC ON TTY
/       IGNORES NULLS
/       PRINTS ^X ON CONTROL CHARS (EXCEPT CR, LF, FF, VT, TAB)
/       PRINTS 'X ON LOWER CASE

/HANDLES TABS CORRECTLY
/       AND AUTOMATICALLY PRINTS CR/LF AT EOL
/       PRINTS ESCAPE AS $

/TTYTLS:        USED TO ACTUALLY PRINT CHAR
/               IT HANDLES TABS AUTOMATICALLY
/               AND CR/LF'S AT END OF LINE

/TTYPCH:        IT USES TTYPRT TO PRINT CHAR BUT ALSO RESPONDS TO
/               ^C, ^O, ^S, ^Q.
/               IF ^Z IS BEING PRINTED, IT THEN STOPS FURTHER PRINTING
\f/MUST BE AT TOP OF PAGE
TTYPCH,                 /ENTRY POINT TO TTY PUNCH ROUTINE
                        /OR TTY PRINT ROUTINE
TTYGCH, 0               /ENTRY POINT TO TTY GET CHAR ROUTINE
        SNA
        JMS TGCH        /ZERO AC-MEANT CALL TO TTYGCH
PCH,    AND (177        /FORCE TO 7-BIT
        DCA TCHAR
        TAD TGCH
M140,   SZA CLA         /ARE WE ECHOING?
        JMP ECHO        /YES, IGNORE ^S AND STUFF
K5,     5               /MUST BE AT REL 10
        TAD TCHAR
        TAD (-32
        IFZERO PAUS <
        SNA CLA
        JMP I TTYPCH
        >
        IFNZRO PAUS <
        SNA
        JMP I TTYPCH
        TAD L15         /32-15
        SNA CLA         /LOOK FOR CR
        ISZ LINCNT      /AT END OF PAGE?
        JMP NOPAUS      /NOT AT CR, OR AT CR BUT NOT AT END OF PAGE
L15,    15              /MUST BE HERE FOR SET
        TAD PAUSN
        DCA TTYTLS      /SET COUNT FOR OUTER LOOP
        ISZ LINCNT
        JMP .-1
        ISZ TTYTLS
        JMP .-3
        TAD LINSYZ
        DCA LINCNT
        >
NOPAUS, JMS TTYTST
        TAD (203-217    /NO
        SNA             /^O?
        DCA TCHAR       /YES, SET TO NULL SO IT WILL BE IGNORED
        TAD (217-223    /NO
        SZA CLA         /^S?
        JMP ECHO        /NO, IGNORE CHAR
TTCTLQ, JMS TTYTST
        TAD (203-221    /NO, NOTHING ELSE MATTERS UNTIL ^Q
        SZA CLA         /^Q?
        JMP TTCTLQ      /NO, SUSPEND OUTPUTTING
TTY32,  KCC             /YES, REMOVE ^Q FROM BUFFER
/HAD NO ROOM FOR:
/       TAD LINSYZ
/       DCA LINCNT
ECHO,   DCA TGCH
        ISZ TTYPCH
        IFNZRO ESC <
        TAD TCHAR
        TAD (-33
        SZA CLA
        JMP .+3
        TAD L44
        DCA TCHAR
L44,    44
        >
        TAD TCHAR
        SNA
        JMP TTYCTO      /IGNORE NULLS
        IFNZRO RUB&4000 <
        TAD (-10
        SNA
        JMP RUBO
        TAD (10-16
        >
        IFZERO RUB&4000 <
        TAD (-16
        >
TTY100, CLL
TTY10,  TAD K5
TTY240, SZA             /TAB?
        JMP NOTAB
        IFNZRO SIMTAB <
TTYTAB, TAD TTY240
        JMS TTYTLS
TTY7,   7               /HERE FOR NO SPECIAL REASON
        TAD TABCTR
        AND TTY7
        SZA CLA
        JMP TTYTAB
        JMP TTYCTO
        >
        IFNZRO SLOTAB <
        TAD TCHAR
        JMS TTYTLS
        TAD (177
        JMS TTYTLS
        TAD (177
        JMP PRIN+1
        >
        IFZERO SIMTAB+SLOTAB <JMP PRIN>

/BUG: IF HARDWARE TABS, DON'T COUNT COLUMNS CORRECTLY

        IFNZRO RUB&4000 <
RUBO,   TAD TTY10       /OUTPUT BACKSPACE-RUBOUT-BACKSPACE
        JMS TTYTLS
        TAD TTY240
        JMS TTYTLS
        TAD (-4
        TAD TABCTR
        JMP PREPRN
        >
\fNOTAB, SZL CLA
        JMP SPCHR       /DON'T UPARROW CHARS LF,CR,TAB,VT,FF
        IFNZRO FLAGLC <
        TAD TCHAR
        AND TTY140
        TAD M140
        SZA CLA         /IS IT LC?
        JMP NOLC        /NO
TTYQUO, "'
        TAD TTYQUO      /YES
        JMS TTYTLS      /PRINT QUOTE
        TAD M40
        JMP PRIN        /PRINT UPPER CASE OF CHAR
        >
NOLC,   TAD TCHAR       /NO, GET BACK CHAR
        AND TTY140      /HIGH ORDER BITS IRRELEVANT
        IFNZRO CTRL <
M40,    SMA SZA CLA     /CAN'T BE NEGATIVE
        JMP PRIN        /NOT A CONTROL CHARACTER
        TAD TTYUPA      /ECHO 201-237 AS ^X (EXCEPT 211-215)
        JMS TTYTLS
        TAD TTY100      /ADD X100 TO ^K TO GET K
        >
        IFZERO CTRL <
        SNA CLA         /IS CHAR A CONTROL CHAR?
        JMP TTYCTO      /YES, DON'T ECHO CONTROL CHARACTERS EXCEPT FOR 211-215
        >
PRIN,   TAD TCHAR
        JMS TTYTLS
TTYCTO, TAD TABCTR      /RETURN TABCNT IN AC
        JMP I TTYPCH

        IFZERO CTRL <
M40,    -40
        >

TTY140,
SPCHR,  STA CLL
        TAD LINSIZ
PREPRN, DCA TABCTR      /THESE CHARS RESET COLUMN COUNTER
        JMP PRIN
\fTGCH,  0               /NON-ZERO MEANS TTYGCH WAS CALLED
        KSF
        JMP .-1         /WAIT FOR CHAR TO BE TYPED
        JMS TTYTST
/WILD: (DON'T PUT IN)   SZA CLA /FALL THRU AND RETURN R.O.
/       ISZ TTYGCH
        TAD (203-377
        SNA CLA         /TAKE RETURN 1 ON RUB OUT
        JMP I TTYGCH    /"CLUMSY" - R.L. (9/18/73)
        ISZ TTYGCH
        KRB             /GET CHARACTER
TTYAND, AND (177        /MUST RETURN CHAR IN 7-BIT
        IFNZRO CNVLC <
        DCA TCHAR
        TAD TCHAR
        AND TTY140
        TAD M140
        SNA CLA         /IS IT LC?
        TAD M40         /YES
        TAD TCHAR       /NO
        >
        IFNZRO ALTMOD <
        TAD (-175       /IS IT 175 OR 176?
        SMA
        JMP CONV        /YES, CONVERT ALTMODE TO ESCAPE
        TAD (175        /NO, RESTORE CHAR
        >
        JMP I TTYGCH    /TAKE RETURN 3

/SHOULDN'T TABCTR BE INITIALIZED TO C(LINSIZ) UPON ENTRY?

TABCTR, -110

TTYTLS, 0
        TLS
        IFNZRO DELAY <
        TAD (-DELAY
        SZA CLA
        STA
        >
TTYTSF, TSF
        JMP .-1
        IFNZRO DELAY <
        IAC
        SZA             /19.66 MS IS G.T. 1/60 SEC
        JMP TTYTSF
        >
        ISZ TABCTR
TTYUPA, "^
TT7600, 7600
        JMP I TTYTLS
LINSIZ, -110

        IFNZRO PAUS <
LINSYZ, -HEIGHT
LINCNT, -HEIGHT
PAUSN,  -PAUS
        >

        IFNZRO ALTMOD <
                IFNZRO KCC-6032 <
CONV,           CLA
                TAD (33
                JMP I TTYGCH
                >
        IFZERO KCC-6032 <
CONV,           CLA IAC
                TAD TTY32       /DEVICE DEPENDENT
                JMP TTYAND
                >
        >
\fTCHAR, 0

/TTYTST:        READS KEYBOARD STATICALLY AND RESPONDS TO ^C
/               OTHERWISE RETURNS CHAR (8-BIT) MINUS 203 IN AC.
/               IF FLAG IS NOT UP, IT RETURNS A 1.

TTYTST, 0
        TAD TT7600      /OR CHAR IN
        KRS
        TAD (-7603      /-7603=175
        KSF
        CLA IAC         /STUFF IN BUFFER IS UNRELIABLE IF FLAG ISN'T UP
        SZA
        JMP I TTYTST
        IFNZRO INDVC-3 <KCC>
        CIF CDF 0       /BRANCH TO OS/8 MONITOR AT 07600
        JMP I TT7600    /IT WILL PRINT "^C" FOR CHAR IN BUFFER
        PAGE
\f/      DYNAMICALLY MODIFYING THE KL8E HANDLER

/       *** I M P O R T A N T ***

/       THIS HANDLER CAN BE DYNAMICALLY CHANGED VIA SET COMMANDS.
/       CONSEQUENTLY, IT IS EXTREMELY IMPORTANT THAT PEOPLE
/       WHO MODIFY THIS SOURCE DO NOT AFFECT THE ALGORITHMS
/       NECESSARY TO PERFORM SUCH MODIFICATIONS.

/       THIS ALGORITHM IS EXPLAINED BELOW.

/       SET TTY WIDTH=N

/       SEARCH LOCATIONS 200-377 FOR A 7600.  CALL ITS ADDRESS X.
/       LET Y BE THE INSTRUCTION AT LOCATION X+1.
/       FORM THE (RELATIVE) ADDRESS T=Y&177+200-1.
/       THEN LOCATIONS T AND X+2 CONTAIN MINUS THE TTY WIDTH.
/       THE WIDTH MUST BE A MULTIPLE OF 10 AND MUST NOT BE 200.
/       (BECAUSE -200 IS THE MAGIC 7600)

/       SET TTY CODE XX

/       SEARCH ENTIRE HANDLER FOR INSTRUCTIONS OF THE FORM 6XXY
/       WHERE XX IS NOT 20 OR 21,
/       AND FURTHERMORE DON'T INCLUDE A 6031 IF 2 LOCATIONS
/       FOLLOWING IS A 7650
/       AND DON'T INCLUDE A 6034 IF 4 LOCATIONS FOLLOWING IS A 7650.


/       SET TTY [NO] ECHO

/       THE WORD INVOLVED IS AT (RELATIVE) LOCATION 120.
/       SET TO 7440 TO ECHO.
/       SET TO 7610 TO SUPPRESS ECHOING.


/       SET TTY LC

/       SEARCH LOCATIONS 200-377 FOR A 377.  CALL ITS ADDRESS X.
/       LOOK AT LOCATION X+5.
/       IF THIS LOCATION IS NOT A 7650, THEN LC TO UC CONVERSION
/       WAS NOT ENABLED AT ASSEMBLY TIME.
/       IF THE FEATURE IS ENABLED, CHANGE LOCATION X+5 TO A 7610
/       TO PREVENT THE CONVERSION.  TO ALLOW CONVERSION, SET
/       LOCATION X+5 BACK TO 7650.

/       SET TTY PAGE

/       SEARCH LOCATIONS 215-300 FOR A 7450. CALL ITS ADDRESS X.
/       SET X+3 TO 7640 TO ENABLE ^S, ^Q.
/       SET X+3 TO 7200 TO DISABLE ^S, ^Q.
\f/      SET TTY TAB

/       SEARCH LOCATIONS 200-300 FOR A 7.
/       IF NOT FOUND, SIMULATED TABS WAS NOT ENABLED AT ASSEMBLY TIME.
/       IF FOUND, CALL ITS ADDRESS X.
/       TO PATCH OUT SIMULATED TABS:
/               MOVE C(X-12) TO LOCATION X-2
/               CHANGE LOCATION X+3 TO A 7610
/       TO RESTORE SIMULATED TABS:
/               SET LOCATION X-2 TO X-4&77+1200
/               CHANGE LOCATION X+3 TO A 7640

/       SET TTY FILL

/       THE LITERAL 177 MUST REMAIN AT THE END OF PAGE 2
/       SEARCH LOCATIONS 200-300 FOR A 1377.
/       IF NOT FOUND, THEN FILL CHARACTERS WERE NOT ENABLED AT ASSEMBLY
/       TIME.  IF FOUND, CALL ITS ADDRESS X.
/       TO PATCH OUT FILL CHARACTERS, MOVE C(X+3) TO LOCATION X-1.
/       TO RESTORE FILL CHARACTERS, MOVE C(X+1) TO LOCATION X-1.

/       SET TTY FLAGLC

/       SEARCH LOCATIONS 200-377 FOR A 247.
/       IF NOT FOUND, LOWER CASE FLAGGING WAS NOT ENABLED AT ASSEMBLY TIME.
/       IF FOUND, CALL ITS ADDRESS X.
/       TO DISABLE FLAGGING, SET LOCATION X-2 TO A 7200.
/       TO RE-ENABLE FLAGGING, SET LOCATION X-2 TO A 7640.

/       SET TTY PAUSE [N]

/       SEARCH LOCATIONS 200-300 FOR A 15.
/       IF NOT FOUND, PAUSING WAS NOT ENABLED AT ASSEMBLY TIME.
/       IF FOUND, CALL ITS ADDRESS X.
/       TO DISABLE PAUSING AFTER A FULL SCREEN,
/       SET LOCATION X-3 TO A 7610.
/       TO RE-ENABLE PAUSING, SET LOCATION X-3 TO A 7650.
/       TO SET PAUSE DURATION, SEARCH LOCATIONS 300-377 FOR A 7600,
/       CALLING ITS ADDRESS X.  THEN (MINUS THE) PAUSE DURATION IS AT
/       LOCATION X+5.

/       SET TTY HEIGHT

/       THIS IS ONLY APPLICABLE IF SET TTY PAUSE HAS BEEN ASSEMBLED IN
/       (A 15 CAN BE FOUND ON SECOND PAGE).
/       NEGATIVE OF HEIGHT MUST BE SET IN BOTH LOCATIONS X+3 AND X+4
/       WHERE X IS THE ADDRESS OF A 7600 AS IN ABOVE.
\f/      SET TTY ESCAPE

/       SEARCH LOCATIONS 200-377 FOR A 44.
/       IF NOT FOUND, THEN $ WAS NOT ASSEMBLED INTO TTY HANDLER.
/       IF FOUND, CALL ITS ADDRESS X.
/       TO DISABLE PRINTING ESCAPE AS $, SET LOCATION X-4 TO A 'CLA'.
/       TO CAUSE ESCAPE TO PRINT AS AN ESCAPE, SET LOCATION X-4 TO SZA CLA.

/       SET TTY ARROW

/       SEARCH LOCATIONS 200-377 FOR 7740.

/       IF NOT FOUND, USING OLD HANDLER.
/       CALL ITS ADDRESS X.
/       IF LOCATION X+1 IS MORE THAN 7000,
/       THEN UPARROW MODE WAS NOT ASSEMBLED INTO KL8E.
/       OTHERWISE, TO ALLOW ARROWS, SET LOCATION X+3 TO THE
/       CONTENTS OF LOCATION X+6.
/       TO CAUSE CONTROL CHARACTERS TO ECHO AS IS, SET
/       LOCATION X+3 TO 'SKP CLA'.
/       NOTE THAT THIS IS A DIFFERENT OPTION THAN ASSEMBLING CTRL=0.
\f       IFDEF TEST <
        *600

/TEST ROUTINE FOR KL8E HANDLER

GO,     JMS I (TTY      /CALL HANDLER
        0600            /READ SIX PAGES
        1000            /BUFFER AT 01000
        0001            /BLOCK 1
        HLT             /ERROR RETURN
        JMS I (TTY      /CALL HANDLER AGAIN
        4600            /OUTPUT SIX PAGES
        1000
        0001
        HLT
        CLA
        JMP GO
        >
        $
\f