;              **** VIDPLOT.ASM  VERSION 1.0 ****
;
; VIDEO PLOT ROUTINES FOR THE TELEVIDEO TPC-1
; CRT CONTROLLER VIDEO GRAPHICS INTERFACE SUBROUTINES
; USED WITH THE 'VIDDUMP.BAS' PROGRAM TO DECODE AND DISPLAY
; '.RLE' (RUN LENGTH ENCODED) FORMAT PIC FILES ON THE TPC-1 
;
;              AUGUST 11,1987 DAVE CLIFFORD 
;              TIME-=<X>=-CHANGE MBBS-RCP/M 
;              (213) 329-3922 300/1200 24HRS...
;
;       ASSEMBLE WITH 'ZM.COM' OR OTHER EQUIV Z-80 ASSEMBLER 
;       AND EDIT RESULTING .HEX CODE FOR USE AS 'DATA' STATEMENTS
;	THEN READ IN TO THE 'VIDDUMP.BAS' FILE.......
;	(SEE 'VIDPLOT.HEX' FILE FOR AN EXAMPLE.)
;*************************************************************
;
; SET BASIC-80 RAMTOP FOR 32766 (&H7FFE)
	ORG	800AH	; LOAD ABOVE BASIC-80
;
; BASIC-80 INTERFACE PRAMETERS EQUATES
;
XAXIS	EQU	8002H	;P1
YAXIS	EQU	8004H	;P2
;
XAXIS1	EQU	8006H	;P3
YAXIS1	EQU	8008H	;P4
;
MARGIN	EQU	8000H	;P5 SCREEN CENTERING OFFSET POKE 32768
;
; INIT GRAPHICS MODE
;
INIT:
	PUSH	BC
	PUSH	DE
	PUSH	HL
	LD	C,1
	CALL	GROUT
	LD	C,2
	CALL	GROUT
	LD	C,0BH
	LD	HL,1
	CALL	GROUT
	LD	C,0CH
	LD	HL,1
	CALL	GROUT
	LD	C,0EH
	LD	HL,1
	CALL	GROUT
	POP	HL
	POP	DE
	POP	BC
	RET
;
; MOVE TO X,Y AND PLOT A PIXEL SUBROUTINE
;
DRAW:
	PUSH	DE
	PUSH	HL
	LD	C,4
	LD	HL,(XAXIS)
	PUSH	BC
	LD	BC,(MARGIN)
	ADD	HL,BC
	POP	BC
	LD	DE,(YAXIS)
	CALL	GROUT
	LD	C,5
	LD	HL,(XAXIS1)
	PUSH	BC
	LD	BC,(ASPECT)
	ADD	HL,BC
	POP	BC
	LD	DE,(YAXIS1)
	CALL	GROUT
	POP	HL
	POP	DE
	RET
;
; GRAPHICS OUTPUT ROUTINE
;
GROUT:
	RST	28H
	RET
;
; DISPLAY GRAPHICS SCREEN
;
GRAPH:
	PUSH	BC
	PUSH	DE
	PUSH	HL
	LD	C,1
	CALL	GROUT
	POP	HL
	POP	DE
	POP	BC
	RET
;
; DISPLAY ALPHA SCREEN
;
ALPHA:
	PUSH	BC
	PUSH	DE
	PUSH	HL
	LD	C,0
	CALL	GROUT
	POP	HL
	POP	DE
	POP	BC
	RET
;
	END