ANGELO S GRIMALDI
Electrical Contractor in Tinton Falls, NJ

6782355, Aug 24, 2004

Mar 10, 2000

09/523053

Robert Bryan Cook - Poughkeepsie NY
Angelo Salvatore Grimaldi - Red Bank NJ
Jeffrey Joseph Ruedinger - Rochester NY

Quickturn Design Systems, Inc. - San Jose CA

G06F 9455

703 23, 703 14

A hardware design emulation system that includes one or more emulators and one or more associated run-time assist units (RTAUs). The emulator logic is a combination of user model logic, reflecting the hardware design, and non-user model logic. A handshaking controller produces a domain step signal and a model step signal. The domain step signal indicates that the emulator is entering a state for executing the next step of the logic with which it is programmed, be it user model logic or non-user model logic. The model step signal indicates that the emulator is entering a state for advancing the user model defined by the user model logic. This dual handshaking protocol enhances versatility by enabling a wide variety of RTAUs to be used, particularly in combination with one another. Also, a RTAU can, in accordance with its programming, “skip steps” (either model steps or domain steps) to enhance efficiency if there is a known relationship between cycles of the emulator logic and cycles of the user model. In addition, system stoppage logic efficiently alerts other RTAUs when one RTAU has caused the emulation to stop.