Add original unix v6

source/s2/pfe.s

@@ -0,0 +1,44 @@
+/ print last floating error
+
+stst	= 170300^tst
+
+	stst	r1
+	cmp	r1,$14
+	blos	1f
+	clr	r1
+1:
+	bic	$1,r1
+	mov	mesg(r1),r1
+1:
+	movb	(r1)+,ch
+	beq	1f
+	mov	$1,r0
+	sys	write; ch; 1
+	br	1b
+1:
+	sys	exit
+
+mesg:
+	1f
+	2f
+	3f
+	4f
+	5f
+	6f
+	7f
+	8f
+
+1:	<No error.\n\0>
+2:	<Floating op code error\n\0>
+3:	<Floating divide check\n\0>
+4:	<Integer conversion error\n\0>
+5:	<Floating overflow\n\0>
+6:	<Floating underflow\n\0>
+7:	<Floating undefined\n\0>
+8:	<Floating maintennace trap\n\0>
+
+	.even
+
+	.bss
+ch:	.=.+2
+