Mon Aug 17 09:18:48 CEST 2009
With the machine organized as it is now, there is really no need for
an IP register: always use the top of RS.
Well, conceptually that's the case, but let's keep it like it is now.
It's an implementation issue that doesn't have too many consequences.
Another thing though: the return stack can't be used for storing
temporary data. Or can it? Looks like it can, at least in the middle
of a SEQ, because an atom placed on RS will only be accessed when
evaluating a primitive or constant in tail position.