> I have an application that writes to an LCD
> with the current count.  This is within a
> fairly critical loop and I'd like to keep
> the timing consistent.
>
> The problem is as the count decreases, the
> conversion function doesn't take as long.
>
> Any thoughts?

Seriously:
Don't put code like this inside timing loops.
Avoid timing loops wherever possible.
Pad with NOPs in the appropriate cases. :-P