title GETFIL - dirty work for the PROGRAM statement
	entry getfn.,ttypr.
	search pasunv
	twoseg
	reloc 400000
maxwd==20		;number of words used to store user's input
maxlen==5*maxwd
file==maxwd+1
defspc==maxwd+2

t0=0
t1=1
t2=2
t3=3
t4=4
d=16			;display
p=17			;main pdl
filnam==14
fileof==1

getfn.::	;t2 = pointer to file block
	push p,d	;standard PASCAL entry sequence
	hrls d,p
	hrri p,maxwd+4(p)
	caig 15,40(p)
	jsp t1,corerr##

	pushj p,initb.##		;block can't possibly be init yet
	movem t3,defspc(d)		;save name as default
	move t1,[point 7,(t3)]		;filename is here
	movei t4,^D10			;and is this long
wrloop:	ildb t0,t1			;use it to prompt user
	outchr t0
	sojg t4,wrloop
	outstr [asciz / : /]
getstr:	move t1,[point 7,1(16)]		;now read spec from user - put here
	movei t4,0			;t4 = counter of char's
getnew:	inchwl t0
	caie t0,12			;check for end of line
	cain t0,33
	jrst readon
	caie t0,32
	cain t0,14
	jrst readon
	caig t0,40			;otherwise ignore funny char's
	jrst getnew			;so t4.gt.0 only if something there
	addi t4,1			;not eol - count it
	caile t4,maxlen
	jrst toolng			;error if too long
	idpb t0,t1			;else save it away
	jrst getnew			;and get next char

toolng:	outstr [asciz /
? File spec too long - try again:
/]
	clrbfi
	jrst getstr
badnam: outstr [asciz /
? Illegal file spec - try again:
/]
	clrbfi
	jrst getstr

readon:	movei t3,1(16)			;starting addr of string
	jumple t4,usedef		;null spec - use default
	movem t2,file(d)
	pushj p,parse##			;other arg's are OK
	move t2,file(d)
	skipe fileof(t2)		;see if valid name
	jrst badnam			;no - try again

done:	hrri p,(d)			;standard exit code
	pop p,d
	popj p,

usedef:		;here if he defaults spec
	caie t2,input##			;for input 
	cain t2,output##		;and output
	jrst usedf1			;default to tty:
	move t3,defspc(d)		;saved address of default
	movei t4,6			;length
	jrst usedf2
usedf1:	movei t3,[asciz /TTY:/]
	movei t4,4
usedf2:	pushj p,parse##			;convert it
	jrst done			;if still error, ignore it

;ttypr. - do initial get for INPUT
ttypr.:	move t0,input##+fildev		;t0 _ this device
	devnam t0,
	  jrst ttyprg			;failed, assume not our tty
	getlin t1,			;t1 _ controlling terminal
	came t0,t1			;do the prompt only if the same
	jrst ttyprg
	outstr [asciz /[INPUT, end with ^Z: ]
/]
ttyprg:	movei t2,input##
	jrst getch##

	end