In the tutorial the register reset is missing. But this isn't a mistake. The tutorial concentrates on the division itself. Of course all used registers must be initiated.

Yes, but is an accepted practice to head all routines with something like (I am not trying to start a discussion about header layout, just stating that a header should be present)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
; blah
;
; blah converts apples to oranges
;
; r4 must contain apple count
; r7 contains orange count

blah:


Erik