An Architectural Approach to Characterizing and Eliminating Sources of Inefficiency in a Soft Processor Design

Abstract

This work takes an architectural approach to systematically characterize components and mechanisms that are the main sources of low operating clock frequency when implementing a typical pipelined general purpose processor on an FPGA. Several previous works have addressed specific implementation inefficiencies, however mostly on a case-by-case basis. Accordingly. there is a need to systematically characterize the sources of inefficiency in soft processor designs. Such a characterization serves to deepen our understanding of FPGA implementation trade-offs and can serve as the starting point for developing FPGA-friendly designs that achieve higher performance and/or lower area. We start with a typical 5-stage pipelined architecture that is optimized for custom logic implementation and that focuses on correctness, modularity, and speed of development.