Add original unix v6

source/s2/mkdir.s

@@ -0,0 +1,91 @@
+/ makdir -- make a directory
+
+	sys	getuid
+	mov	r0,uid
+	mov	sp,r5
+	tst	(r5)+
+
+loop:
+	tst	(r5)+
+	dec	(sp)
+	bgt	1f
+	sys	exit
+1:
+	mov	(r5),r0
+	mov	$buf1,r1
+	mov	$buf2,r2
+	clr	r3
+1:
+	movb	(r0)+,r4
+	beq	2f
+	movb	r4,(r1)+
+	movb	r4,(r2)+
+	cmpb	r4,$'/
+	bne	1b
+	mov	r2,r3
+	br	1b
+2:
+	movb	$'/,(r1)+
+	movb	$'.,(r1)+
+	clrb	(r1)
+	mov	$dot,dir
+	tst	r3
+	beq	1f
+	mov	$buf2,dir
+	clrb	(r3)
+	cmp	r3,$buf2+1
+	beq	1f
+	clrb	-(r3)		/ ???
+1:
+	tstb	uid
+	beq	2f
+	sys	stat; dir:..; stbuf	/ status of parent dir
+	bes	error
+	mov	stbuf+4,r0
+	cmpb	uid,stbuf+7
+	bne	1f
+	ash	$-6,r0
+1:
+	ror	r0
+	ror	r0
+	bcc	error			/ no write permission in parent
+2:
+	mov	(r5),0f
+	sys	makdir; 0:..; 140777; 0
+	bes	error			/ prob already exists
+	mov	(r5),0f
+	sys	chown; 0:..; uid:..
+	mov	(r5),0f
+	sys	link; 0:..; buf1
+	bes	error
+	movb	$'.,(r1)+
+	clrb	(r1)
+	mov	dir,0f
+	sys	link; 0:..; buf1
+	bec	loop
+
+error:
+	mov	(r5),r0
+	mov	r0,0f
+	clr	0f+2
+1:
+	tstb	(r0)+
+	beq	1f
+	inc	0f+2
+	br	1b
+1:
+	mov	$1,r0
+	sys	write; 0:..; ..
+	mov	$1,r0
+	sys	write; ques; 3
+	br	loop
+
+dot:	<.\0>
+ques:	< ?\n>
+	.even
+
+.bss
+buf1:	.=.+100.
+buf2:	.=.+100.
+stbuf:	.=.+40.
+