KGPMAP - LIBRARY-BASED TECHNOLOGY-MAPPING TECHNIQUE FOR ANTIFUSE BASED FPGAS

Owing to their high degree of flexibility and low design-turnaround ti me, Field-programmable-gate-array (FPGA) based designs are becoming ve ry popular. With the availability of different types of FPGA, the need of a unified approach for logic-block-independent technology mapping is being felt increasingly. The paper presents a new approach to effic ient realisation of a given combinational function in terms of a presp ecified k-input-single-output logic block. All subfunctions of 1 to k inputs realisable by the logic block are generated and kept in a libra ry. The approach is general in the sense that it is not targeted to an y specific FPGA built around a specified set of basic blocks. It uses a node-clustering technique for breaking up the given combinational fu nction into subfunctions with special treatment for the fanout nodes. The scheme utilises a novel signature-based strategy to find a match f or a subfunction in the library. One contribution is the elegant signa ture-generation scheme that can be applied for any library-based searc h problem. The signature is unique for functions of up to four variabl es and has an aliasing of around 0.5% for functions with larger number of variables. For comparison with other mapping techniques, the KGPMA P algorithm has been applied to several combinational benchmark circui ts using Actel's act1-library. The result has been found to be superio r to other well known library-based technology mappers and some Actel- specific mappers.