Dual delay mode pipelined logic simulator

Abstract

Logic simulation is performed using special purpose hardware which operates in either one of two simulation modes. The machine allows detailed timing simulation where each device may be programmed with a delay time of zero, one, or multiple simulation time units. In addition, the machine supports zero and unit delay simulation in a high performance 'unit delay' mode. The logic simulation function is partitioned into six sub-functions which are implemented in a single stage of a six-stage pipeline. The pipeline stages which implement the multi-unit delay time queue management may be switched to perform a different algorithm for unit delay simulation. The machine is able to perform extremely fast functional circuit testing and to perform detailed timing simulation without changing the circuit 'netlist'.