Optimum functional decomposition for LUT-based FPGA synthesis

Abstract

In general, Partially Dependent Functions(PDFs) are meaningful for sharing multiple-output CLBs or an LUT. In this paper, we present a novel encoding algorithm for detecting PDFs during functional decomposition. To exploit all solution space, we have introduced pliable encoding to supplement the classical rigid encoding as the latter failed to catch a satisfactory solution. We show that the best solution can only be found by pliable encoding in some cases, and hence the classical encoding strategy should be modified to take account of pliable encoding. Experimental results on a set of MCNC91 benchmarks are quite encouraging.