New insights on Ling adders

Adders are critical for microprocessor design. Current designs use variations of parallel prefix schemes. A method introduced by Ling [7] may improve this kind of adders. However, as recent research publications demonstrate, the use of the Ling scheme in prefix adders is not a mature and clear concept. In this work we show how to easily extend any existing prefix adder topology to use the Ling method. Moreover, we use this methodology to implement the Ling scheme in a flagged prefix adder, which is an interesting building block for floating point units.