Abstract: A hardware monitoring interface unit (HMIU) is coupled to a data processing unit and receives all information transferred between subsystems of the data processing unit. Programmable hit matrices (PHM's) include input latches for receiving the information, memory circuits for storing binary ONE's in locations addressed by predetermined portions of the information and output latches for storing the binary ONE's or "hit" signals read from the memory circuits. The "hit" signals are plug-wired into logic circuits and counters in a monitor to collect statistical data.

Abstract: A hardware monitor interface unit (HMIU) is coupled to a data processing system. Programmable hit matrices (PHM's) in the HMIU store information which is compared with information from the data processing system. The PHM's generate "hit" signals indicating comparison. These "hit" signals are received by monitors coupled to the HMIU which are used to compile the data processing system performance data. Appartus in the HMIU generates clocking signals enabling the information to be received by the HMIU and generates strobing signals to be used for timing the "hit" signals and other control signals received by the monitors.

Abstract: A data processing system includes a number of subsystems, all coupled in common to a system bus. Also coupled to the system bus is a hardware monitor interface unit (HMIU) for receiving all information transferred between subsystems. The HMIU includes programmable hit matrices (PHM's). The PHM's include memory circuits which generate "hit" signals when predetermined information addresses the memory circuits. The "hit" signals or binary ONE's are loaded into the memory circuits during a load mode during which system bus information specifically addressing the HMIU is received on two system bus cycles for each address location of the memory circuit. The data bus contains the memory circuit address during the first system bus cycle and the data during the second data bus cycle. An address bus signal identifies the cycle.

Abstract: A monitor interface unit couples a monitor to a data processing system which includes a central processing unit (CPU). The monitor generates data for determining the performance of the data processing unit. The monitor interface unit includes apparatus for stopping the CPU clock during a particular CPU operation and then slowing down the CPU clock rate.