MENT.

/ 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 RELIABILITP I IEXIT5	/FOR CONTROL Z PROCESSING FROM OUTPUT SIDE ONLY.
	TAD (32-15	/^Z MINUS CR
	SNA
	JMP CRLF
	TAD (15-12	/CR-LF
	SNA CLA
	JMP I XMIT2	/DON'T PASS LF CHARACTERS 
	TAD XMIT3	/HERE TO 
	JMS XMIT6
	JMP I XMIT2

CRLF,	TAD (215
	JMS XMIT6
	TAD (212
	JMS XMIT6
	JMP I XMIT2

ALLSET,	TAD ALL2
	DCA ENTRY1
ALL2,	JMP I IRENTRY	/BEGIN PROCESSING.

TEMPOINT,
DEVINPUT			/ PARITY, OVERRUN, FRAMING, HARDWARE ERRORS
	DEVREC=6306	/ LOAD RECEIVE BUFFER INTO AC
	DEVXMT=6316	/ LOAD TRANSMIT BUFFER FROM AC
	DEVACC=6366	/ ACCESS COMM CONTROLER INTERNAL REGISTER
			/ NOTE:ODD/EVEN DATA FIELD DETERMINE WHAT INFORMATION
			/ IS GOING TO BE READ.


	*0
	7777
	DEVICE COMM
	DEVICE COMM
	0050
	ENTRY&177+4000
	0000
	0000

	*200


RENTRY,
ZEROSW,			/ WHEN CLEAR, BUFFER IS BEING ZEROED PRIOR TO EXIT.
BUFRFD,	CDFXXX
	ISZ RXSWITCH	/ IF -1, FUNCTION IS XMIT
	JMP RECV0	/ INPUT

/ TRANSMIT ROUTINES. THERE ARE NO "ERROR CONDITIONS" FOR OUTPUT. ALL TERMINATION
/ WILL RETURN TO CALLER AT +5 (NORMAL EXIT) WITH THE C(AC)=0. POSSIBLE RETURN
/ CONDITIONS ARE: 1) BUFFER IS EMPTY;  2) ^Z WAS FOUND IN BUFFER. A ^C WILL
/ RETURN TO MONITOR AT 7600. XON/XOFF IS RECOGNIZED FOR THE OUTPUT DEVICE.

XMIT,	TAD CRCHAR	/ SEND ONE TIME CR TO MAKE BASIC HAPPY
	JMS I IXMIT6
	DCA XMIT
	DCA XMIT+1
XMIT1,	ISZ WRDCNT
	JMP XMIT1A
EXIT5,	TAD ZEROSW
	SZA CLA
	ISZ ENTRY
XITFLD,	CDFIFX
	JMP I ENTRY
XMIT1A,	STL
	RTL
	RTL
	SPA
	JMP XMIT1B	/ FOR CHAR3
	DCA CHAR3
CDF1,	CDFXXX
	TAD I BUFRPT
	JMS I IXMIT
CDF2,	CDFXXX
	TAD I BUFRPT
	ISZ BUFRPT
	7400		/ SERVES AS A NOP TO PROTECT ISZ
	AND .-1
	CLL RAL
	TAD CHAR3
	JMP XMIT1A+1
XMIT1B,	JMS I IXMIT
	JMP XMIT1	/ FOR ANOTHER PASS

CDFCIF,	CDF CIF 0
K3700,	3700
CRCHAR,	15

IXMIT,	XMIT2-PAGE2
IXMIT6,	XMIT6-PAGE2
IDEVINPUT,DEVINPUT-PAGE2

/ INPUT ROUTINES. ACCEPTS INPUT FROM THE DEVICE AND RETURNS 8-BIT ASCII
/ TO THE CALY OF ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY
/ DIGITAL.


	VERSION="B&77^100+61

	NOCHK=	0	/ 0 = No ctrl c test, 1 = test

	AC0004=CLA CLL IAC RTL
	AC100=CLA IAC BSW
	AC4000=CLA STL RAR
	ACM2=CLL CLA CMA RAL
	BSW=7002
	XON="Q&77
	XOFF="S&77
	CDFXXX=HLT
	CDFIFX=HLT

	DEVSKP=6301	/ SKIP ON FOLLOWING COMM CONDITIONS
			/ TRANSMIT FLAG
			/ RECEIVE FLAG
5-12)
	SNA CLA
	JMP RECV1	/ DON'T PASS LINE FEEDS
	ISZ BUFRPT	/ UPDATE BUFFER POINTER
ZMINCR,	32-15
	ISZ WRDCNT
	JMP RECV1	/ FOR THE NEXT
	JMP EXIT5

RECV6,	ISZ ENTRY	/ SINCE A "CLEAR" ZEROSWITCH WON'T BUMP IT FOR EXIT.
	DCA ZEROSW
	TAD XXOFF
	JMS I IXMIT6	/ SEND XOFF AFTER CR
	ISZ BUFRPT
LF,	12		/ (LINEFEED; USED TO PROTECT ISZ)
	TAD LF
CDF4,	CDFXXX
	DCA I BUFRPT
	ISZ BUFRPT
XXOFF,	XOFF
	JMP ZMINCR

XXON,	XON
WRDCNT,	0
K70,	70
BUFRAD,	0
BUFRPT,	0
RXSWITCH,
CHAR3,	0	
MINZ,	-32		/ -^Z
CRMLF,	15-12

/			TRAILING DATA BLOCK FOR HANDLER CALL:

/	WORD	1 FUNCTION WORD  _ _ _ ! _ _ _ ! _ _ _ ! _ _ _
/				 ! \ 	     /   FIELD   UNUSED
/		       4000= WRITE   DOUBLE      OF      IN 
/		       0000= INPUT   WORDS ^100  BUFFER  OS/78

/	WORD	2 ADDRESS OF BUFFER
/	WORD	3 STARTING BLOCK. IF 0, MAY DO SPECIAL INIT ROUTINES;
/			          OTHERWISE IS IGNORED FOR THIS HANDLER
/	WORD	4 ERROR. IF AC IS POSITIVE, ERROR IS NOT CONSIDERED FATAL.
/	WORD	5 NORMAL RETURN. AC IS 0.

	*340

ENTRY,	VERSION
	AC4000		/ FORCE THE WRITE (OUTPUT BIT) INTO THE LINK IF
	TAD I ENTRY	/ PRESENT WHEN GETTING THE FUNCTION WLING PROGRAM BUFFER. INPUT CHARACTERS ARE SCREENED FOR A
/ ^Z, CR(LF).  ^Z IS THE ONLY CHARACTER THAT WILL CAUSE
/ AN "ERROR" EXIT. THERE ARE NO FATAL ERRORS. ^Z AND CR WILL ECHO CRLF, PAD
/ THE CALLING PROGRAM BUFFER WITH ZERO BEFORE EXITING.

RECV0,	TAD WRDCNT
	CLL IAC RAL	/ INPUT RETURNS 1 8BIT PER 1 12BIT WORD TO CALLER.
	DCA WRDCNT
	TAD XXON
	JMS I IXMIT6
RECV1,	TAD ZEROSW	/ WHEN ZERO, WE ARE PADDING USER BUFFER PRIOR TO EXIT.
	SZA CLA
	JMS I IDEVINPUT	/ GET A CHARACTER FROM INPUT.
CDF3,
RECV1A,	CDFXXX
	DCA I BUFRPT	/ RETURNS 8BIT ASCII.
	TAD I BUFRPT	/ USE THE CALLING BUFFER FOR TEMP STORAGE.
	TAD MINZ	/ -^Z (-32)
	SNA
	JMP XITFLD	/ ^Z FOUND EXIT
	TAD ZMINCR	/ ^Z-CR (32-15)
	SNA
	JMP RECV6	/ CARRIAGE RETURN
	TAD CRMLF	/ CR-LF  (1CA BUFRAD
	TAD BUFRAD
	DCA BUFRPT	/ WILL HAVE CURRENT POSITION OF USER'S BUFFER.
	ISZ ENTRY	/ SKIP THE BLOCK NUMBER (THIS IS NON-FILE STRUCTURED)
	ISZ ENTRY	/ AND LEAVE RETURN POINTING TO ERROR.
	RDF		/ DATA FIELD IS SET TO CALL; INSTRUCTION FIELD IS HERE.
	TAD CDFCIF
	DCA XITFLD	/ WHEN EXITING, IF/DF IS SET TO CALLING ROUTINE.
	TAD BUFRFD
	DCA CDF1
	TAD BUFRFD
	DCA CDF2
	TAD BUFRFD
	DCA CDF3
	TAD BUFRFD
	DCA CDF4
CDF0,	CDF 0		/ FALL THRU TO NEXT PAGE FOR INDIRECT ADDRESS ADJUSTMENT


	PAGE


/ PROCEDURE FOR ADJUSTING THE ABSOLUTE ADDRESSES OF INDIRECT LOCATIONS:

/ THIS HANDLER IS ASSEMBLED WITH A STARTING LOCATION OF 200. THIS IS PARTLY
/ ARBITRARY AND PARTLY BECAUSE OF THE REQUIREMENTS OF THE BUILD PROGRAM.
/ A "MARK" IS ESTABLISHED TO BE USED DURING ASSEMBLY TIME TO SET THE VALUE
/ OF THE INDIRECT ADDRESS POINTERS TO THE RELATIVE DIFFERENCE BETWEEN THE 
/ POINTER AND THE ROUTINE REQUESTED. FOR CONVENIENCE, THIS MARKER IS CALLED
/ "PAGE2" AND IS ESTABLISHED AT THE TOP OF THE SECOND PAGE. THE ADJUSTMENT
/ ROUTINE FINDS THE BASE ABSOLUTE ADDRESS FROM THE "JMS ." THEN ADDS IT
/ TO THE THE VALUE IN "DIFFORD. MUST BE
	AND K70		/ PRESERVED WHILE FETCHING REST OF DATA BLOCK.
	TAD CDF0
	DCA BUFRFD	/ GET THE FIELD OF THE BUFFER
	SZL
	STA
	DCA RXSWITCH	/ 0=RECEIVE; -1=XMIT
	TAD K3700	/ AND THE "DOUBLE WORDS". FOR OUTPUT, WILL REPRESENT
	AND I ENTRY	/ 2 PACKED WORDS OF 3 ASCII CHARS. IF INPUT, WILL BE
	CMA		/ DOUBLED TO COUNT 1 8BIT CHARACTER FOR EACH 12BIT WORD.
			/ NOTE: OS/8 ROUTINES CAN REQUEST THE PROCESSING OF A
			/ NULL BUFFER (ZERO DOUBLE WORDS). IF SOME SPECIAL
			/ ACTION IS REQUIRED, E.G. WRITING EOF OR DOING FORM
			/ FEED, THE WORD COUNT WILL BE ZERO. THIS HANDLER MAY
			/ OR MAY NOT HAVE SPECIAL FUNCTIONS, DEPENDING UPON
			/ ASSEMBLY SPECIFICATIONS.
	DCA WRDCNT
	ISZ ENTRY
	TAD I ENTRY	/ GET THE STARTING ADDRESS OF THE BUFFER.
	D
	IXMIT6-PAGE2
	IDEVINPUT-PAGE2
XMIT3,	IEXIT5-PAGE2
XOFFLAG,IRENTRY-PAGE2

XMIT2,	0		/ SCREEN CHARACTER BEFORE OUTPUT
	AND (177
	DCA XMIT3	/ SAVE CHARACTER.
XMIT2B,	JMS DEVIN1	/ CHECK DEVICE FOR XON/OFF
	SNA
	JMP XMIT2D	/ NO FLAG
	TAD (-XON	/ IS IT XON
	SNA		/ NO
	JMP XMIT2A	/ YES
	TAD (XON-XOFF	/ IS IT XOF
	SNA CLA		/ NO
	JMP XMIT2C	/ YES, SET XOFF FLAG
XMIT2D,	ISZ XOFFLAG	/ WORKING ON XOFF ALREADY?
	JMP XMIT2A	/ NO. IGNORE THE INPUT
XMIT2C,	STA		/ [RE]SET THE FLAG
	DCA XOFFLAG
	JMP XMIT2B	/ AND KEEP LOOKING.
XMIT2A,	DCA XOFFLAG	/ KEEP CLEARED WHEN NOT WORKING ON XOFF.
	TAD XMIT3
	TAD (-32
	SNA
	JMP I IEXIT5	/ FOR CONTROL Z PROCESSING FROM OUTPUT SIDE ONLY.
	TAD (32-15	/ ^Z MINUS CR
	SNA
	JMP CRLF
	TAD (15-12	/ CR-LF
	SNA CLATABLE". THE CONTENTS OF DIFFTABLE ARE THE
/ RELATIVE DIFFERENCES BETWEEN PAGE2 AND THE INDIRECT ADDRESS POINTERS TO
/ BE MODIFIED. THIS DIFFERENCE PLUS THE BASE ABSOLUTE ADDRESS FORMS AN
/ ABSOLUTE POINTER TO THE ADDRESS TO BE MODIFIED. THE CONTENTS OF THE AD-
/ DRESS TO BE MODIFIED IS ALSO THE RELATIVE DIFFERENCE BETWEEN THE MARK
/ AND THE ADDRESS DESIRED. USING THE TEMPORARY ABSOLUTE POINTER, THIS DIF-
/ FERENCE IS ADDED TO THE BASE ADDRESS THEN RESTORED TO THE INDIRECT
/ POINTER AS AN ABSOLUTE VALUE.



ENTRY1,	NOP		/ GETS JMP I IRENTRY AFTER INIT.
PAGE2A,	JMS .		/ TO FIND OUT WHERE WE ARE. LEAVE 2A SO WE CAN MOVE.
PAGE2,
ADJUST,	TAD DIFFTABLE
	SNA
	JMP ALLSET
	TAD PAGE2A	/ AS THE BASE.
	DCA TEMPOINT
	TAD I TEMPOINT
	TAD PAGE2A
	DCA I TEMPOINT
	ISZ ADJUST
	JMP ADJUST

XMIT6,	0
	CDF 0
	DEVXMT		/ SEND CHARACTER
	JMS COMCHK	/ WAIT FOR XMIT FLAG
	JMP .-1		/ HANG IT
XMIT6A,	TAD (50		/ SHOULD RETURN HERE BY HARD JUMP
	DEVACC		/ 50 = CLEAR TRANSMITTER FLAG
	JMS DEVCLR	/ NOW CLEAR INTERRUPT CONDITION
	JMP I XMIT6

IEXIT5,	EXIT5-PAGE2
IRENTRY,RENTRY-PAGE2

DIFFTA,	IXMIT-PAGE2	/ SET UP CROSS PAGE LINKAGEDEVACC
OS8MON,	7600
	JMP I DEVCLR	
	
CHKTTY,	0
IFNZRO	NOCHK < KSF >
IFZERO	NOCHK < NOP >
	JMP I CHKTTY
	KRB
	TAD (-3		/IS IT A CTRL C DMII IS ALWAYS 7 BIT
	SZA CLA
	JMP I CHKTTY
	CDF CIF 0
	JMP I OS8MON	/BEFORE EXITING TO MONITOR