;***************************************************************************;
;									    ;
;		     Hazeltine Esprit II Terminal Driver		    ;
;									    ;
;			  Author: David F. Pallmann			    ;
;	     Copyright (C) 1984 by LMS Technical Services, Inc.		    ;
;									    ;
;***************************************************************************;

OBJNAM	ESPRIT.TDV

;universals
SEARCH	SYS
SEARCH	SYSSYM
SEARCH	TRM

LI=233					;lead-in code (escape)

;ASCII chars
BS=10
LF=12
CR=15

;Terminal driver communications area

ESPRIT:	WORD	TD$NEW			;terminal attributes
	BR	JMPINP			;input routine
	RTN				;output routine
	BR	ECHO			;echo routine
	BR	JMPCRT			;crt control
	RTN				;no init routine yet
	WORD	0			;no impure area yet
	BYTE	24.			;number of rows
	BYTE	80.			;number of columns
	LWORD	TD$LID!TD$DIM!TD$EOL!TD$EOS

JMPINP:	JMP	INP			;go handle input characters
JMPCRT:	JMP	CRT			;go handle tcrt codes

;ECHO
;Special echo processing is performed here.
;DEL will backspace and erase the previous character.
;^U will erase the entire line by backspacing and erasing.

ECHO:	CMPB	D1,#'U-'@		;^U
	BEQ	CTRLU
	CMPB	D1,#177			;DEL
	BNE	ECHX

;DELs are handled by the old backspace-and-erase game.
;Special handling must be performed if we are deleting a <TAB>.
;D6 contains the character being deleted.

RUBOUT:	CMPB	D6,#'I-'@		;was it a tab?
	BEQ	RBTB			;  yes

;DEL was of a printable character - queue up the backspace sequence
KRTG:	MOV	#3,D3			;set character count
	LEA	A6,ERUB			;set buffer address
	MOV	A6,D1			;  into d1
	TRMBFQ				;queue the backspace sequence
	RTN
ERUB:	BYTE	10,40,10,0

;DEL was of a <TAB> - calculate how big the <TAB> was and backup over it.
RBTB:	CLR	D3			;preclear D3
	MOVW	T.POB(A5),D3		;set beginning position count
	MOV	T.ICC(A5),D2		;set input character count
	MOV	T.IBF(A5),A6		;set input buffer base
KRTS:	DEC	D2			;done with scan?
	BMI	KRTQ			;  yes
	MOVB	(A6)+,D1		;scan forward calculating position
	CMPB	D1,#11			;<TAB>
	BEQ	KRTT
	CMPB	D1,#15			;<CR>
	BEQ	KRTC
	CMPB	D1,#33			;<ESC>
	BEQ	KRTI
	CMPB	D1,#40			;control character
	BLO	KRTS
	CMPB	D1,#172
	BHI	KRTS
KRTI:	INC	D3			;increment position for one character
	BR	KRTS
KRTT:	ADD	#10,D3			;adjust position for <TAB>
	AND	#^C7,D3
	BR	KRTS
KRTC:	CLR	D3			;clear position for <CR>
	BR	KRTS
KRTQ:	COM	D3			;calculate necessary backspaces
	AND	#7,D3
	INC	D3
	MOV	#10,D1			;set immediate backspace character
	TRMBFQ				;queue the backspaces
ECHX:	RTN

;Echo a control-U by erasing the entire line.
CTRLU:	TST	D6			;no action if nothing to erase
	BEQ	CTUX
	CLR	D3			;preclear D3
	MOVW	T.POO(A5),D3		;calculate backspace number to erase the line
	SUBW	T.POB(A5),D3
	BEQ	ECHX
	CMP	D3,T.ILS(A5)		;insure not greater than terminal width
	BLOS	CLUA
	MOV	T.ILS(A5),D3
CLUA:	MOV	#10,D1			;queue up backspaces
	TRMBFQ
	ASL	D1,#2			;queue up spaces
	TRMBFQ
	MOV	#10,D1			;queue up backspaces
	TRMBFQ
CTUX:	RTN

;INP
;Input character processing subroutine.
;Return a negative flag to indicate possible multi-byte key codes.
;Detect a negative flag which indicates the multi-byte processing return.
INP:	AND	#177,D1			;strip char to 7 bits
	LCC	#0
	RTN

PAGE
;CRT
;Special crt control processing.
;D1 contains the control code for X,Y positioning or special commands.
;If D1 is positive we have screen positioning (row in hi byte, col in lo).
;If D1 is negative we have the special command in the low byte.

CRT:	TSTW	D1			;is it cursor position?
	BMI	CRTS			;  no

;Cursor positioning - D1 contains X,Y coordinates
	TTYI				;send position command
	BYTE	LI,17.,0,0
	ADD	#<95._8.>-1,D1
	CMPB	D1,#31.
	BHIS	100$
	ADDB	#96.,D1
100$:	TTY				;send column first
	ROR	D1,#8.
	TTY				;send row second
	RTN

;Special commands - D1 contains the command code in the low byte
CRTS:	AND	#377,D1			;strip the high byte
	BNE	CRTU			;  and branch unless clear screen
	TTYI				;special case for clear screen
	BYTE	LI,28.,0
	EVEN

;output some <NUL>s after screen-oriented functions
CRTZ:	MOV	#45.,D0
	CLR	D1
10$:	TTY
	SOB	D0,10$
	RTN

;Command processing per director tables
CRTU:	PUSH	A2			;save A2
	ASL	D1			; times 2 (word offset).
	CMP	D1,#CRCB-CRCA		;check for valid code
	BHI	CRTX			;  and bypass if bad
	LEA	A2,CRCA-2		;index the table
	ADD	D1,A2			;add command code
	MOVW	@A2,D1			;pick up data field offset
	ADD	D1,A2			;make absolute data address
	TTYL	@A2			;print the data field
	CMPB	@A2,#36			;sleep if home command
	BEQ	CRTXZ
	CMPB	1(A2),#100		;sleep if erase command
	BHI	CRTXZ
CRTX:	POP	A2			;restore A2
	RTN

CRTXZ:	POP	A2			;restore A2
	BR	CRTZ			;  and go output nulls

;Byte offset and data tables follow for all commands
CRCA:	WORD	C1-.,C2-.,C3-.,C4-.,C5-.,C6-.,C7-.,C8-.
	WORD	C9-.,C10-.,C11-.,C12-.,C13-.,C14-.,C15-.,C16-.
CRCB:
PAGE

DEFINE	CRT	CODE1,CODE2,CODE3
	IF	NB,CODE1,BYTE CODE1
	IF	NB,CODE2,BYTE CODE2
	IF	NB,CODE3,BYTE CODE3
	BYTE	0
	ENDM

C0:	CRT				;clear screen
C1:	CRT	LI,22			;cursor home
C2:	CRT	CR			;cursor return
C3:	CRT	LI,14			;cursor up
C4:	CRT	LF			;cursor down
C5:	CRT	BS			;cursor left
C6:	CRT	20			;cursor right
C7:	CRT	LI,25			;lock keyboard
C8:	CRT	LI,6			;unlock keyboard
C9:	CRT	LI,17			;erase to end of line
C10:	CRT	LI,'W-'@		;erase to end of screen (background only)
C11:	CRT	LI,31			;low intensity
C12:	CRT	LI,37			;high intensity
C13:	CRT	LI,37			;enable prot. fields
C14:	CRT	LI,31			;disable prot. fields
C15:	CRT	LI,19.			;delete line
C16:	CRT	LI,26.			;insert line
	EVEN

	END

.