METHOD FOR SIMULTANEOUSLY BEGINNING EXECUTION OF USER CODE UPON A PLURALITY OF EMULATORS

A system for coordinating the measurement activity of a plurality of emulators and their associated internal analyzers uses a bus with three signal lines. A READY signal is set false by any emulator that initiates a break (a transition from running user code to running a monitor). The READY signal is set false by the breaking emulator at the very beginning of its break, without waiting for the resumption of the monitor program. The false ready signal is detected immediately by the other emulators, which then break in sympathy. The READY signal is further used to restart all emulators in unison. The emulator that initiated the break remains running its monitor, while the others start their monitors, determine that they did not cause the break, and then in anticipation of a restart, essentially suspend their monitors and prepared to start running user code. As each emulator becomes ready it releases the READY signal. As the last emulator becomes ready, it too releases READY, which then does true. At this all emulators complete their escape from their monitors (which for each of them amounts to just an instruction fetch, or so) and resume execution of their user code.