Derivation of signal flow direction in MOS VLSI: an alternative

Novel rules to derive the signal flow in a VLSI-design are presented. This method is based on design-style independent logical principles, which makes it suitable for circuits that have not been checked on their electrical correctness. The use of two global principles has an important influence for more complicated designs, but also results in an efficiency penalty which may be kept reasonable by introducing graph reduction rules and heuristics. The different steps in the tagging process are explained and illustrated with examples. The dataflow rules are integrated in the overall DIALOG system to perform electrical verification, and they offer an invaluable help to break up the verification problem in subproblems and to cope with feedback in designs, by introducing the concept of intended unilateral blocks