Multiplier (BCT)

Multiplies inputs A and B. The result is twice the width or a word.

The multiplier starts by EORing the multiplicand (A input) with the trits of the multiplier (B input). This calculates the partial products quickly and in parallel. Next the 9 partial products need to be added together to get the final result.

This can be done with 8 series adders but just like the Ripple Carry Adder the operations add up and take a very long to propagate through and calculate the final product.

However, these adds do not need to be done in order. The 9 partial products can be separated into three groups of three. The carry select adder design is expanded to do three input addition. The three groups of three are added together in parallel followed by those results also getting added and finishing the final result.

This setup not only takes far fewer logic, but it's also three times faster.