[LCP]Base 2 logarithms

[Chuck Martin]

What's the best way to calculate base 2 logarithms?  I know that I could
use log(x)/log(2) or log10(x)/log10(2), but I'm not sure which of those
is the most efficient, and it seems that since all computers today, with
the possible exception of some experimental computers, do all of their
calculations in binary, there ought to be a simple and fast way to do
this natively without the complexity of either of the above methods.  Is
there?

Chuck