Decomposition of multi-output functions oriented to configurability of logic blocks

Abstract

Abstract The main goal of the paper is to present a logic synthesis strategy dedicated to an LUT-based FPGA. New elements of the proposed synthesis strategy include: an original method of function decomposition, non-disjoint decomposition, and technology mapping dedicated to configurability of logic blocks. The aim of all of the proposed synthesis approaches is the sharing of appropriately configured logic blocks. Innovation of the methods is based on the way of searching decomposition, which relies on multiple cutting of an MTBDD diagram describing a multi-output function. The essence of the proposed algorithms rests on the method of unicoding dedicated to sharing resources, searching non-disjoint decomposition on the basis of the partition of root tables, and choosing the levels of diagram cutting that will guarantee the best mapping to complex logic blocks. The methods mentioned above were implemented in the MultiDec tool. The efficiency of the analyzed methods was experimentally confirmed by comparing the synthesis results with both academic and commercial tools.