Patent ID: 8676560

Claim:
A simulation method for simulating a physical unit controlled by an electronic control unit, the method comprising the steps of: operating a physical unit simulator through computer processing continuously for a fixed number of multiple steps in a speculative simulation; recording, upon completion of the physical unit simulator operating for the fixed number of multiple steps, a time of a speculative input event corresponding to an end of the fixed number of multiple steps, the speculative input event and an internal state variable in a rollback table in a readable manner through computer processing; receiving at the physical unit simulator an output event, including a time of the output event, from an electronic control unit emulator; determining, by a global scheduler, an oldest event recorded in the rollback table by either the physical unit simulator or the electronic control unit emulator; updating a determinate time to a time of the oldest event in the rollback table, wherein the oldest output event is marked as a determinate entry in the rollback table; notifying the electronic control unit emulator and the physical unit system simulator of the determinate time; setting the physical unit simulator back to the determinate time corresponding to a time of the determinate entry upon determining an inconsistency between the time of the output event from the electronic control unit emulator and the time of the speculative input event recorded in the rollback table; operating the physical unit simulator up to the time of the output event from the electronic control unit emulator.