I think it's at eight or so for eight bit (I would have to go check), ten for 16 bit, twelve for 32 bit. It uses lattice multiplication to find all the partial sums and add them simultaneously.
Basically you just add two ticks for each doubling in size.
Here is how you build it.
http://en.m.wikipedia.org/wiki/Dadda_multiplier
Basically you just add two ticks for each doubling in size.
Here is how you build it.
http://en.m.wikipedia.org/wiki/Dadda_multiplier