MR. MICHAEL TRUMAN ROBINSON, DO
Marriage and Family Therapists at Front St, Medford, OR

5805859, Sep 8, 1998

Jun 7, 1995

8/477149

David J. Giramma - Portland OR
Thomas E. Roth - Portland OR
Oliver W. Kozber - Beaverton OR
Michael G. Robinson - Portland OR
David K. Johnson - Aloha OR

Synopsys, Inc. - Mountain View CA

G06F 9455, G06F 1750

395500

Described is a circuit modifier, network, and method for use with an event-driven digital logic simulator for enforcing consistent evaluation of input pin changes at state elements. The invention automatically interposes a fictitious 0-delay defer agent or processor, at the input pin to state elements such as D Flip-Flops. The interposition of the defer agent is handled by the simulator as follows. Defer agents schedule events related to input state changes on a special time or task queue which is not processed until after all other events have been executed for the current time, including any extra iterations caused by 0-delay scheduling activity. Defer agents or processors are placed in a simulation network just prior to one or more of the input pins of state elements, the effect of which is to delay events that normally would propagate to the input pin of a state element until all other normal simulation events are processed. Once the normal simulation events have been executed, the defer events are executed which permits the inputs of the state elements to change after other simulation events have been executed, thereby ensuring consistent evaluation of pin changes at state elements.