Add original unix v6

source/tmg/tmgb/arith.s

@@ -0,0 +1,56 @@
+.globl succ,fail,iget
+.globl seekchar,getword,alterword
+.globl sprv,update
+.globl .l,.u,.p,.t,.st,
+
+/ infix =
+.st:
+	jsr	pc,sprv
+	mov	(sp)+,(sp)
+	mov	(sp)+,(sp)
+/ update
+.u:
+	jsr	pc,update
+	br	9f
+/ pop stack
+.p:
+	jsr	pc,sprv
+	cmp	(sp)+,(sp)+
+	br	9f
+/ test stack
+.t:
+	jsr	pc,sprv
+	mov	(sp)+,(sp)+
+	bne	9f
+	jmp	fail
+/ load named value
+/ rvalue into (sp), lvalue into 2(sp)
+.l:
+	jsr	pc,iget
+	mov	r0,-(sp)
+	mov	(r0),-(sp)
+	br	9f
+/ update a stored value, used by all assignments
+update:
+	cmp	2+2(sp),$-1
+	beq	1f
+	mov	0+2(sp),*2+2(sp)
+	rts	pc
+1:
+	mov	4+2(sp),r1
+	mov	6+2(sp),r0
+	jsr	pc,seekchar
+	mov	0+2(sp),r0
+	jsr	pc,alterword
+/ make sp hold a simple rv (forget it might be a table value)
+sprv:
+	mov	(sp)+,r0
+	cmp	$-1,2(sp)
+	bne	1f
+	mov	(sp)+,(sp)
+	mov	(sp)+,(sp)
+1:
+	mov	r0,pc
+9:
+	jmp	succ
+