Microword control mechanism utilizing a programmable logic array and a sequence counter

摘要

A microword control mechanism is provided for producing the sequences of microwords used to control the execution of processor instructions in a microprogrammed data processor. This microword control mechanism includes circuitry (15, 20) responsive to a processor instruction to be executed for providing an instruction dependent signal uniquely representative of such instruction. This microword control mechanism also includes sequence counter circuitry (18) for supplying a sequence of number signals. This microword control mechanism further includes a programmable logic array (17) responsive to the instruction dependent signal and to the sequence of number signals for producing a sequence of microwords needed to execute the processor instruction.