3 Input Adder

[ASRS_]

Hey!

A friend of mine has figured out the logic of how to make a 3 input adder. Here is a diagram of the logic:

So far, me and a group of people have been able to make a fully functional RCA:

And also a fully functional vertical CCA:

The problem is that the vertical CCA is a little slow, and we weren't able to figure out a good way to get it faster.
It uses a little different logic than the diagram since it has some CCA logic included, but theres probably a better way to implement it.
It would be interesting to see what you people would be able to do.

[jxu]

Your "3 input adder" is essentially carry-save addition (one carry-save adder and one standard adder). Functionally a normal adder is already a 3 input adder (rename carry in to input c)

https://people.clarkson.edu/~linh/algori...dition.pdf

[Nickster258]

Just pasting this here as I found this patent quite interesting. https://patents.google.com/patent/US4783757A/en

[Nuuppanaani]

I built a 3 input PLA adder some years ago using a real life carry design. Can't remember if it's what Nick just linked but might have been. Cool stuff, I can see uses for these in specialized circuits!

[jxu]

Just pasting this here as I found this patent quite interesting. https://patents.google.com/patent/US4783757A/en

Am I missing something? This is also just two layers of carry-save adders.