Richard Erlacher wrote:
>
> I'd say they're pretty practical for shallow stacks. However, when one is
> exploring the realm of stack-driven architectures, you need a pretty deep one.
> Admittedly, I completely spaced the shift register approach to stacks, but
> that was because the deepest stack I'd ever seen with shift registers was
> about 2K deep. That was an old-timer, though. It used a bunch of 2513 shift
> registers (in TO-5 cans) on a board dedicated to that purpose.
Wow - can's that is REAL old and expensive logic.
> > Shift register stacks do have the advantage of being fast. Did not the
> > 8008 or the 4004 use a 8 level stack for subroutine calls. A calculator
> > chip at that time only needed 4 functions.
> >
> That seems reasonable, but in what time-frame are you thinking?
Late 1970's. While more functions are useful, Most low end calculators
($3?) just do the 4 functions.
--
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html
Received on Sat Apr 13 2002 - 11:44:35 BST