Pattern matching and refinement hybrid approach to circuit comparison

We present a new approach to circuit comparison which was developed to combine general applicability with most of the advantages of hierarchical processing. The basic principle of operation is the pattern matching of arbitrary subcircuits in larger circuits. Typically, a hierarchical schematic has to be compared with a flat netlist extracted from the layout. In our approach, this is accomplished by successive, bottom-up matching of schematic cells in the layout netlist, thus reconstructing the schematic hierarchy. The method is independent of circuit technology and design style. A sophisticated hierarchy handling scheme enables the usage of ill-structured schematic hierarchies. The typical problems in circuit comparison are overcome in a quite natural way by pattern matching. Real-life examples indicate the tool´s suitability in function and performance. The hybrid approach is a mixture between the pattern matching approach and the traditional refinement technique. In this way, the advantages of both methods can be exploited