On Fri, 20 Oct 2000, Bob Ammerman wrote:

>
> No, 'known_zero' is a RAM location that is zeroed at initiali(s,z)ation and
> then left alone. The cycle it takes to do that isn't counted for purposes of
> the challenge because it can be done once and forgotten.

BTW, one way to make a know_zero without ccnsuming any extra ram is to use
FSR. In most (not all) applications, FSR is re-initialized each time it's
used. In those cases, it can be cleared before a long arithmetic computation
(like Tony's 24-bit multiplication routine). The beauty of this is that the FSR
my be accessed from any bank. Furthermore, you can use INDF as known_zero too
(if fsr is cleared). I imagine if your goal was to write obfuscated code (with
the intent of discouraging reverse engineering), then this would be one clever
trick to keep in your bag.


Scott

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu