A Coarse-Grain Phased Logic CPU

Abstract

This paper describes an asynchronous design tool flow known as phased logic that converts a clocked design into an asynchronous design implemented as a micropipeline using two-phase control and bundled data signaling. Example designs include variations of a double-precision floating-point clipping operation mapped to two commercial standard cell libraries (0.18/spl mu/ and 0.13/spl mu/) and a five-stage pipelined MIPs-compatible integer unit mapped to the 0.13/spl mu/ library. The design style includes a feature known as early evaluation, which is a generalized form of bypass that allows the self-timed design to recover some of the inherent latch delay penalty in micropipelines.