A hierarchical compiled code event-driven logic simulator

Logic simulation techniques that reduce both preprocessing time and execution time of unit delay logic simulation are described. Compiled code implementation techniques using a threaded code organization are applied to the event-driven logic simulation algorithm. Simulation speed is increased by a factor of tip to 10 by this technique compared to conventional event-driven simulation. The technique is then extended to hierarchical simulation, in which a fan-out procedure and simulation procedure are generated for each unique module. Hierarchical simulation reduces preprocessing time and allows the recompilation of only those modules that are modified. The simulator uses a portable machine model in which an architecture file describes the target machine. The simulator can be quickly ported to new machines by defining the architecture, while still obtaining high performance