Enhancing timing-driven FPGA placement for pipelined netlists

Abstract

FPGA application developers often use pipelining, C-slowing and retiming to improve the performance of their designs. Unfortunately, registered netlists present a fundamentally different problem to CAD tools, potentially limiting the benefit of these techniques. In this paper we discuss some of the inherent issues pipelined netlists pose to existing timing-driven placement approaches. We then present two algorithmic modifications that reduce post-routing critical path delay by an average of 40%.