Method Of Tracing Asynchronous Multiple Level Interrupts
Original Publication Date: 1979-May-01
Included in the Prior Art Database: 2005-Feb-20
The figures show a method of tracing asynchronous multiple level interrupts using a microcode program. Knowing which level interrupts were serviced and in which order and if multiple level interrupts were taken is very helpful in defining problems in a priority interrupt system. The standard procedure is to provide a history register that logs all instructions in sequence. The most recent instruction overlays the oldest instruction such that the last performed series of instructions are available.