[Libre-soc-dev] Paper about Dadda vs Wallace multiplier efficiency

[Jacob Lifshay]

On Tue, Dec 29, 2020, 16:55 Luke Kenneth Casson Leighton <lkcl at lkcl.net>
wrote:

> On Tuesday, December 29, 2020, Cole Poirier <colepoirier at gmail.com> wrote:
> > Found an insightful paper about multiplier latency and gate count because
> Richard had some questions about it after Luke had to go today. Will post
> on the wiki resources page once I’m at my keyboard.
>
> star.
>
> i remember from the discussions jacob and i had: wallace is easier to do
> partitioning wise because the adds are just standard adds, one after the
> other.
>

not quite...

>
wallace is actually nearly identical to dadda, since both of them have a
tree of carry-save adders (a carry-save adder is just a list of 1-bit
full-adders with no carry propagation -- pretty simple) that convert 3
terms to 2 terms then a final standard adder to add the last 2 terms. the
difference between wallace and dadda is just in how the tree is structured
a little differently.

Jacob