;****************************************************************
;* 								*
;*								*
;*	DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY *
;*	EITHER FOR THE CREATION OR FOR THE CLINICAL EFFICACY	*
;*	OF THIS PROGRAM. USERS MUST ASSUME FULL RESPONSIBILITY	*
;*	FOR ANY RESULTS OR DIAGNOSES OBTAINED FROM THE USE	*
;*	OF THIS PROGRAM. QUESTIONS ON THE EXECUTION OF THIS	*
;*	PROGRAM MUST BE REFERRED BACK TO THE ORIGINAL AUTHOR.	*
;*								*
;* AUTHOR:	SALLY FORSTER					*
;*		C/O DEPARTMENT OF NUCLEAR MEDICINE		*
;*		GUY'S HOSPITAL					*
;*		LONDON, ENGLAND					*
;*								*
;*		TEL: 01-407-7600 EXT 2583/4			*
;*								*
;****************************************************************
	.TITLE	VSVPB	PLOT N MATCHED PAIRS
;CALL CLEAR
;CALL BOX(I)
;CALL PLOTB(X,Y,N,P,C)
;X&Y BYTES CONTAINING THE N PAIRS OF POINTS**RANGE 0-127
;POINTS PLOTTED AS COLOUR C ON L.U.T.P
	.GLOBL	PLOTB,VGCSR,VGBUF,VGPC,VGCOLR
PLOTB:	MOV	%0,-(%6)	;SAVE REGISTERS
	MOV	%2,-(%6)
	MOV	%1,-(%6)
	MOV	%3,-(%6)
	MOV	%4,-(%6)
	ADD	#2,%5
	MOV	(%5)+,%2	;X ARRAY ADDR.
	MOV	(%5)+,%3	;Y ARRAY ADDR.
	MOV	@(%5)+,%4	;NUMBER OF POINTS
	MOV	@(%5)+,PIX	;L.U.T. ID
	MOV	@(%5)+,COL	;PLOT COLOUR
	BIC	#400,@VGCSR
	MOV	PIX,%5
	CLR	%0
2$:	CLC
	INC	%0
	ASL	%5
	CMP	%0,#10
	BNE	2$
	MOV	%5,PIX+2
10$:	MOVB	(%2)+,%0
	MOVB	(%3)+,%1
	SUB	#127.,%1
	NEG	%1
	CLR	%5
20$:	CLC
	ASL	%1
	INC	%5
	CMP	%5,#5
	BNE	20$
	CLR	%5
	CLC
	ROR	%0
	BCC	30$
	ADD	#1,%5
30$:	CLC
	ROR	%0
	BCC	40$
	ADD	#2,%5
40$:	BIS	%1,%0
50$:	TSTB	@VGCSR
	BPL	50$
	MOV	%0,@VGPC
	ADD	VGBUF,%5
	MOVB	PIX,(%5)
	DEC	%4
	BNE	10$
	CLR	@VGCOLR
	ADD	PIX+2,COL
	MOV	COL,@VGCOLR
	BIS	#400,@VGCSR
	MOV	(%6)+,%4
	MOV	(%6)+,%3
	MOV	(%6)+,%1
	MOV	(%6)+,%2
	MOV	(%6)+,%0
	RTS	%7
PIX:	.=.+4
COL:	0
	.END	PLOTB