Flame Re: pussyfooting

[Keith Packard]

To all of you who hate the 4.2 cat program, here is a fix (at least for
those on vaxen).  I, too, didn't like it when I typed cat -n and
mysterious numbers appeared in the output.  What follows is a *very*
simplistic cat program.  It is also fast.  I don't believe I have ever
seen it take *any* user time at all.  (this includes catting
30 or 40 copies of /usr/dict/words).  If the file name is - it
reads standard input at that point.  Anything else starting with
a - is ignored (this eliminated much frustration with man).  Also,
when run with

cat door

it properly respondes with:

cat: cannot open door

instead of the silly 4.2 cat that says

door: No such file or directory.

	keith packard
	...!tektronix!reed!keith		(school)
	or
	...!tektronix!reed!motel6!keith		(home)
	or
	...!tektronix!azure!keithp		(work)

--------------------------- cut me here ---------------------------
/*
 *	cat.s
 *
 *	to make me, type
 *
 *	as -o cat cat.s
 *	chmod +x cat
 *
 *	rapidly catenate files to stdout
 */
	.align	1
	.set	bufsiz,49152
/*
 *	define system call values
 */
	.set	exit,1
	.set	read,3
	.set	write,4
	.set	open,5
	.set	close,6
/*
 *	callg frames for system routines
 */
	.data	1
error:	.ascii	"cat: could not open "
errors:	.int	3
	.int	2
	.int	error
	.int	20

errorf:	.int	3
	.int	2
errorn:	.int	0
errorl:	.int	0

opens:	.int	2
fname:	.int	0
	.int	0

closes:	.int	1
cdes:	.int	0

exits:	.int	1
status:	.int	0

	.text
start:	.word	0x000
	cmpl	(sp),$1			# > 1 arg ?
	jneq	mult			# yup, do files
	clrl	r0			# copy stdin
	jsb	cat
done:	movl	$exits,ap
	chmk	$exit

mult:	addl3	sp,$8,r10		# set r10 as arg pointer
floop:	movl	(r10)+,r8		# get file name
	jeql	done			# at end?
	cmpb	(r8),$45		# - opt, read stdin
	bneq	real			# no, real file
	tstb	1(r8)			# check second char
	bneq	floop			# unknown option, skip
	clrl	r0			# copy stdin
	jsb	cat
	brb	floop			# back for more
real:
	movl	r8,fname		# save pointer in callg frame
	movl	$opens,ap		# set ap to start of frame
	chmk	$open			# interupt to open routine
	bcs	badfile			# couldn't open file
	movl	r0,cdes			# save file des in close frame
	jsb	cat			# cat file
	movl	$closes,ap		# close file
	chmk	$close
	brb	floop			# back for more
badfile:
	movl	$errors,ap		# write out error message
	chmk	$write
	movl	r8,errorn
	movl	$1,r0
badlen:	tstb	(r8)+
	beql	badend
	incl	r0
	brb	badlen
badend: movl	r0,errorl
	movb	$10,-(r8)
	movl	$errorf,ap
	chmk	$write
	incl	status
	brb	floop

	.align	1
	.lcomm	buf,bufsiz
	.data
/*
 *	callg frames for read and write
 */
reads:	.int	3
indes:	.int	0
	.int	buf
	.int	bufsiz

writes:	.int	3
	.int	1
	.int	buf
outlen:	.int	bufsiz

	.text
cat:	movl	r0,indes		# save file des in read frame
	jbr	cgo

cloop:	movl	$writes,ap
	chmk	$write
cgo:	movl	$reads,ap
	chmk	$read
	movl	r0,outlen		# save num chars in write frame
	jgtr	cloop

	rsb