COMMENT ⊗   VALID 00002 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002		title	/look/
C00004 ENDMK
C⊗;
	title	/look/
start:	movni	1,1		;getlin wants neg arg
	getlin	1		;get the line number
	tlnn	1,20000		;is it a dd?
	jrst	[outstr	[asciz	/ Not a data disk, can't map
/]
		exit]
	subi	1,20		;make it a physical line number
	hrrm	1,line		;deposit line number
	move	1,[400017,,map]	;setup word for spacewar process
	spcwgo	1,

loop:	inchrw	1
	cain	1,"+"
	jrst	forwrd
	cain	1,"-"
	jrst	backwd
	cain	1,15		;carriage return to exit
	exit
	setzm	direct		;set direction to 0 to stop movement
	jrst	loop
forwrd:	movei	2,1		;set direction forward
	skipa
backwd:	movei	2,-1		;set direction backward
	movem	2,direct
	jrst	loop

map:	sosle	timec		;n'th tic?
	dismis			;no
	movei	10,4		;default n = 4 for 1 map per second
	movem	10,timec
	skipn	direct		;aren't moving
	dismis
	move	10,direct
	addb	10,chanel	;current dd channel being looked at
	andi	10,37		;mask out all but bottom 5 bits
	movn	10,10		;prepare for shift right
	hrlzi	11,400000
	lsh	11,(10)
line:	cono	340,21		;default line is mine
	datao	340,11
	dismis

timec:	0			;start with 1 map per second
chanel:	0			;initial chanel is 0
direct:	1			;initial direction is forward

	end	start