Recursive bisection based mixed block placement

Abstract

Many current designs contain a large number of standard cells intermixed with larger macro blocks. The range of size in these "mixed block" designs complicates the placement process considerably; traditional methods produce results that are far from satisfactory. In this paper we extend the traditional recursive bisection standard cell placement tool Feng Shui to directly consider mixed block designs. On a set of recent benchmarks, the new version obtains placements with wire lengths substantially lower than other current tools. Compared to Feng Shui 2.4, the placements of a Capo-based approach have 29% higher wire lengths, while the placements of mPG are 26% higher. Run times of our tool are also lower, and the general approach is scalable.