Extraction of finite state machines from transistor netlists by symbolic simulation

The paper describes a new technique for extracting clock level finite state machines (FSMs) from transistor netlists using symbolic simulation. The transistor netlist is preprocessed to produce a gate level representation of the netlist. Given specifications of the circuit clocking and input and output timing, simulation patterns are derived for a symbolic simulator. The result of the symbolic simulation and extraction process is the next state and output function of the equivalent FSM, represented as Ordered Binary Decision Diagrams. Compared to previous techniques, our extraction process yields an order of magnitude improvement in both space and time, is fully automated and can handle static storage structures and time multiplexed inputs and outputs.