The MOSSIM Simulation Engine Architecture and Design

Abstract

As the complexity of VLSI circuits approaches 10 to the power of 6 devices, the computational requirements of design verification are exceeding the capacity of general purpose computers. To provide the computing power required to verify these complex VLSI chips, special purpose hardware for performing simulation is required. Existing simulation engines which perform logic simulation are inadequate for MOS VLSI because they cannot accurately model MOS circuits. Switch-level simulation, on the other hand, models the affects of capacitance and transistor ratios at speeds comparable to logic simulation. The MOSSDM Simulation Engine (MSE) is a special purpose processor for performing switch-level simulation of MOS VLSI circuits. A single processor MSE perfonns switch=level simulation 200 to 500 times faster than a VAX 11/780. Several MSE processors can be connected in pallel to achieve additional speedup. A virtual processor mechanism allows the MSE to simulate large circuits with the size of the circuit limited only by the amount of backing store available t o hold the circuit description. Functional simulation is provided on the MSE to facilitate the efficient simulation of large circuits.