;
; SUBROUTINES & MAINLINE TASKS AND A RAM
;
;
KEYIN:  EQU     004             ; INPUT CHAR from KEYBOARD - MSB set if valid character
KEYOUT: EQU     012		; ACK keyboard interface

OSCP0:	EQU	8 		; SCOPE OUTPUT 0
OSCP1:	EQU	9		; SCOPE OUTPUT 1

; TERMINAL DEPENDENT CONSTANTS
WIDTH: 	EQU	110		; PRINTER WIDTH IN OCTAL
CR: 	EQU 	15		; CAR RET CHAR C ASC 1 I Cf\= 1 S
LF: 	EQU 	12		; LINE FEED CHAR (ASC I I LF=1 2>
ESC: 	EQU 	175		; ENTER COMMAND HOOE C ASCI I ESC= 17S )
ETX:	EQU 	3		; CONTROL C EXIT TO STRT .
C: 	EQU 	103		; REQUIRED TO ECHO ETXr - c
UPARR0:	EQU 	136		; REQUIRED TO ECHO ETX, -c
BLANK: 	EQU 040
BUFFSZ: EQU 310
NUMROW: EQU 5
NUMCOL: EQU 20
	ORG 001#000
BUFFER: DATA *200
ADPTR:  DATA *1
COLUM:  DATA *1
ROM:    DATA *1

	ORG	002#000
; ASCII TABLE OF DATA
ASCTAB:
        DATA    000,000	; @ - starburst
	DATA	340,037	; A
	DATA	214,037	; B
	DATA	230,177	; C
	DATA 	206,037	; D
	DATA 	230,036	; E
	DATA 	370,137	; F
	DATA 	210,077	; G

	DATA 	144,037	; H
	DATA 	233,173	; I
	DATA 	273,173	; J
	DATA 	374,125	; K
	DATA 	234,177	; L
	DATA 	344,155	; M
	DATA 	344,147	; N
	DATA 	200,177	; O

	DATA 	360,037	; P
	DATA 	200,167	; Q
	DATA 	360,027	; R
	DATA 	211,037	; S
	DATA 	373,173	; T
	DATA 	244,177	; U
	DATA 	174,175	; V
	DATA 	144,167	; W

	DATA 	177,145	; X
	DATA 	377,153	; Y
        DATA    033,175 ; Z
	DATA	000,000 ; [
	DATA	000,000 ; \
        DATA    000,000 ; ]
        DATA    000,000 ; ^
        DATA    000,000 ; _

        DATA	377,177 ; space
	DATA	377,173	; !
	DATA	357,175	; "
	DATA	343,033	; #
	DATA	201,173	; $
        DATA    000,000 ; %
        DATA    000,000 ; &
	DATA 	377,157	; ’

	DATA	000,000 ; (
        DATA    000,000 ; (
	DATA 	177,001	; *
	DATA	377,035	; +
	DATA 	277,172	; ,
	DATA 	377,037	; -
	DATA 	377,176	; .
	DATA 	177,175	; /

	DATA 	000,175	; 0 - BLOCK 11;61;1 /0 through 9/
	DATA 	377,173	; 1
	DATA 	222,037	; 2
	DATA 	203,037	; 3
	DATA 	345,037	; 4
	DATA 	211,137	; 5 
	DATA 	210,037	; 6
	DATA 	173,175	; 7

	DATA 	200,037	; 8
	DATA 	341,037	; 9
	DATA 	277,137	; :
	DATA	373,037	; ;
	DATA 	377,165	; <
	DATA 	177,157	; =
        DATA    000,000 ; >
        DATA	000,000 ; ?		

BEGN: 
	JMP STRT

OUTPUT:	
	CPI 037		; control character?
	JTC OUTCTL    	; yes, go to special handler
	LHI \HB\ASCTAB 	; POINT AT BEGINNING OF ASCTAB
        NDI 077		; STRIP 2 MSBS
	RLC		; multiply by two
	LLA		; becomes index into table
	LCM		; fetch first byte
	INL		; point to second byte
	LDM		; fetch second byte
; save into output buffer
	LHI \HB\ADPTR 	; POINT to add location
	LLI \LB\ADPTR
	LAM		; get current pointer to A
	LLA		; move to L
        LMC             ; SAVE high byte
        INL
        LMD             ; save low byte
        INL
	CPI 310		; end of page?
        JFZ OUT2	; no - just save
        LLI 000         ; reset to top of page
OUT2:
        LAL
	LLI \LB\ADPTR   ; point to add ptr
	LMA		; save it
        RET		; return

OUTCTL:
	LHI \HB\ADPTR 	; POINT to add location
	LLI \LB\ADPTR

	CPI 12		; line feed?
	JFZ OUTCR
	ADI 052
	CPI 320
	RTC		; just return if at bottom

OUTCT1:
	LMA		; save it
	RET		; return
OUTCR:
	CPI 15
	RFZ		; drop char if not CR

			; 
	RET

DISPLAY:
	LHI \HB\BUFFER	; buffer ptr into HL
	LLI \LB\BUFFER
	LCI 5		; row counter	
DISP0:
	LDI 20		; column counter - 20 chars per row
DISP1:
	LAM		;
	OUT OSCP0	; output first byte to port 0
	INL		;
	LAM
	OUT OSCP1	; output second byte to port 1
	INL
 	DCD		; end of line?
       	JFZ DISP1	; branch if not
	DCC		; done with page?
	JTZ DISP2	; yes branch to send new page
	LAI 125		; end of line char
	OUT OSCP0	; output it
	JMP DISP0	; continue with next row
DISP2:
	LAI 200		; end of page char
	OUT OSCP1	; output it
	RET		; all done

INIT:
	LLI BUFFSZ      ; first zero entire buffer page
	LHI \HB\BUFFER	;
	LCI 377         ; P0 output char0
	LDI 177		; P1 output char1
INIT1:	
        DCL
	LMD             ; P1 output char to mem
	DCL 
	LMC             ; P0 output char to memory
	JFZ INIT1       ; finish initalizing buffer
        LCI 0           ; store zeros, the rest of the way
        LDC
INIT2:	
	DCL 
	LMD             ; P1 output char to mem
	DCL
	LMC             ; P0 output char to memory
	LAL		;
        CPI BUFFSZ      ; end of buffer?
        JFZ INIT2	; no, continue
        RET
	
;
; HERE IS THE ROUTINE TO READ FROM KEYBOARD INTERFACE
; destroys C & D
; returns character in A
INPUT:
        INP     KEYIN   ; read keyboard
        NDA             ; set sign if  a new character present
        RET             ; return character in A with MSB set

;
; MINI EXEC (for test)
;
STRT:
	CAL INIT	; initialize output buffer and pointer
	LAI 100 	; for test purposes, start with a starburst
	CAL OUTPUT	; output it
	LAI 040 		; now a space
	CAL OUTPUT	; output it
	LAI 101 	; output 'A'
	CAL OUTPUT	
	LAI 132 	; output 'Z'
	CAL OUTPUT	
	LAI 060 	; output '0'
	CAL OUTPUT	
	LAI 071 	; output '9'
	CAL OUTPUT	;

STRT1:
	CAL DISPLAY	; display buffer on scope
	CAL INPUT       ; check keyboard
        JFS STRT1       ; no new character
        OUT KEYOUT      ; ack character read
	NDI 177      	; clear MSB
	CAL OUTPUT      ; add to output buffer
	JMP STRT1       ; continue display/polling