Extracting RTL models from transistor netlists

This paper addresses the problem of deriving a register-transfer level (RTL) model from a transistor-level circuit. Using existing techniques, the transistor-level circuit is converted into a relation that describes the evolution of the signals in the circuit with respect to the simulator clock. This simulation relation is then manipulated to derive the stable behavior of the circuit. Given this stable behavior and information about the clocking scheme, we determine if the circuit is combinational, asynchronous or synchronous. For combinational and synchronous circuits we derive an equivalent register-transfer level model. This development enables full-custom circuit designers to use tools that were till now available only to designers working at the gate-level. The algorithm has been successfully used to characterize several custom designs, as well as the entire AT&T standard-cell library.