Insertion Demonstrations of Digital Gallium Arsenide OBP-80 Final Technical Report. Volume 4. OBP80 Software Model. Draft.

Martin Marietta constructed SIMCPU, a component level modeling environment for the GaAs OBP design. The modeling environment is composed of Behavioral Language Models BLMs for each component, Mentor Graphics Quicksim tool, and software to couple them together. The resulting environment had two purposes 1 To allow accurate, component-level timing simulations of the complete GaAs CPU to be run in a reasonable amount of time and 2 To provide the basis for which the detailed transistor level chip design and simulation tasks were compared against the register transfer level simulator, CPUSIM. To accomplish these goals, the complete GaAs CPU simulation had to be driven by a microprogram which was running in CPUSIM, It also had to be capable of providing system level timing decisions, such as the performance lost be altering the ratio of CPU to memory speed.