Add original unix v6

source/s2/sum.s

@@ -0,0 +1,81 @@
+/ sum -- check sum file
+
+	mov	(sp)+,r3
+	tst	(sp)+
+loop:	dec	r3
+	bgt	1f
+	sys	exit
+1:
+	clr	bcnt
+	mov	(sp)+,0f
+	sys	open; 0:..; 0
+	bec	3f
+	mov	$1,r0
+	sys	write; 1f; 2f-1f
+	br	loop
+1:	<oprd\n>
+2:	.even
+3:	mov	r0,r1
+	clr	r5
+1:
+	mov	r1,r0
+	sys	read; buf; 512.
+	bes	err
+	tst	r0
+	beq	print
+	inc	bcnt
+	mov	$buf,r2
+2:
+	movb	(r2)+,r4
+	add	r4,r5
+	adc	r5
+	sob	r0,2b
+	br	1b
+
+err:
+	mov	$1,r0
+	sys	write; 1f; 2
+
+print:
+	jsr	pc,decml
+	mov	$1,r0
+	sys	write; bl; 1
+	mov	bcnt,r5
+	jsr	pc,decml
+	mov	$1,r0
+	sys	write; nl; 1
+	mov	r1,r0
+	sys	close
+	br	loop
+1:	<? >
+nl:	<\n>
+bl:	< >
+	.even
+
+decml:
+	mov	r0,-(sp)
+	mov	r1,-(sp)
+	mov	r5,r1
+	jsr	pc,1f
+	mov	(sp)+,r1
+	mov	(sp)+,r0
+	rts	pc
+
+1:
+	clr	r0
+	dvd	$10.,r0
+	mov	r1,-(sp)
+	mov	r0,r1
+	beq	1f
+	jsr	pc,1b
+1:
+	mov	(sp)+,ch
+	add	$'0,ch
+	mov	$1,r0
+	sys	write; ch; 1
+	rts	pc
+
+.bss
+ch:	.=.+2
+bcnt:	.=.+2
+buf: .=.+512.