Abstract: A logic simulation processor stores in a shift register intermediate values generated during the logic simulation. The simulation processor includes multiple processor units and an interconnect system that communicatively couples the processor units to each other. Each of the processor units includes a processor element configurable to simulate at least a logic gate, and a shift register associated with the processor element. The shift register includes multiple entries to store the intermediate values, and is coupled to receive the output of the processor element. Each of the processor units further includes one or more multiplexers for selecting one of the entries of the shift register as outputs to be coupled to the interconnect system. Each of the processor units may further include a local memory for storing data from, and loading the data to, the simulation processor.

Abstract: A logic simulation processor uses multi-state logic (e.g., in 4-state, signals may take the values 0, 1, X or Z in the simulation of a semiconductor chip design). Typically a reduced number of basic multi-state logic functions are selected for the instruction set of the processor. Logic functions that are not part of the basic set are simulated by constructing them from combinations of the basic logic functions. In this way, the instruction length remains a manageable size but all logic functions that may occur can be simulated. The basic VLIW architecture can be extended to other applications.