Desynchronize a legacy floating-point adder with operand-dependant delay elements

De-synchronization is a fast and simple way to design an asynchronous circuit, but it has inherent limitation on performance improvement due to the traditional delay element implementation method. In this paper, a length-variable delay element is introduced to help us design a high performance asynchronous floating-point adder. The completion time can be automatically adjusted depending on the operation and operand; therefore, the useless waiting time and energy are effectively eliminated. The experimental result shows that our proposal has 33% performance advantages over the synchronous version and the traditional desynchronized implementation.