Abstract: There is disclosed an interrupt arrangement for use in a multiprocessing system where it is desired to specifically direct interrupts from one processor to any other processor. The arrangement treats the interrupt signal as a data communication between processors. In this regard, common address space is set aside, on a system basis, for interrupt signals. A sending processor first contends for the system bus and then addresses a message to a specific target processor. The message is received at the target processor over the regular communication channel and stored in a FIFO memory. Interrupt messages filter through the memory in order of arrival and cause interrupts to occur at the target processor. The information at the output of the FIFO memory controls the processing of the interrupt.

Abstract: The disclosed microprocessor support system provides a total "laboratory" environment for developing and testing application software as well as for debugging the microprocessor-based application machine itself. The microprocessor support system contains a time shared minicomputer equipped with a full set of peripherals which functions as the main or operating system. A data link connects this operating system with test equipment located at the site of the application machine. This test equipment consists of a field test unit which provides an interface between the application machine, a local keyboard terminal and the operating system such that an engineer at the site of the application machine has access through the field test unit to both the microprocessor-based application machine and the operating system with its sophisticated hardware and software resources to assist in developing and testing application software, as well as debugging the application machine itself.