Add original unix v6

source/s1/dsw.s

@@ -0,0 +1,95 @@
+/ dsw - delete from tty
+
+	cmp	(sp)+,$2
+	blt	1f
+	tst	(sp)+
+	mov	(sp)+,0f
+1:
+	sys	stat; 0:dot; stbuf
+	bes	error
+	mov	stbuf+4,r0
+	bic	$!60000,r0
+	cmp	r0,$40000
+	bne	error
+	mov	0b,0f
+	sys	open; 0:..; 0
+	bes	error
+	mov	r0,r1
+1:
+	clrb	buf+17.
+	mov	r1,r0
+	sys	read; buf; 16.
+	bes	done
+	tst	r0
+	beq	done
+	tst	buf
+	beq	1b
+	mov	0b,r2
+	mov	$obuf,r3
+2:
+	movb	(r2)+,(r3)+
+	bne	2b
+	mov	$buf+2,r2
+	dec	r3
+	cmpb	-1(r3),$'/
+	beq	2f
+	movb	$'/,(r3)+
+2:
+	movb	(r2)+,(r3)+
+	bne	2b
+	sys	stat; obuf; stbuf
+	bes	error
+	bit	$60000,stbuf+4
+	bne	1b
+	mov	$buf+2,r2
+2:
+	tstb	(r2)+
+	bne	2b
+	movb	$' ,-(r2)
+	sub	$buf+1,r2
+	mov	r2,0f
+
+2:
+	mov	$1,r0
+	sys	write; buf+2; 0:..
+	clr	r0
+	sys	read; ch; 1
+	cmpb	ch,$'\n
+	beq	1b
+	clr	r0
+	sys	read; ch1; 1
+	cmpb	ch1,$'\n
+	beq	3f
+4:
+	clr	r0
+	sys	read; ch; 1
+	cmpb	ch,$'\n
+	beq	2b
+	br	4b
+3:
+	cmpb	ch,$'x
+	beq	done
+	cmpb	ch,$'y
+	bne	2b
+	sys	unlink; obuf
+	bes	error
+	br	1b
+
+done:
+	sys	exit
+
+error:
+	mov	$1,r0
+	sys	write; mes; 2
+	sys	exit
+
+dot:	<.\0>
+mes:	<?\n>
+
+	.bss
+obuf:	.=.+100.
+stbuf:	.=.+40.
+buf:	.=.+18.
+ch:	.=.+1
+ch1:	.=.+1
+