MICROCODE CONTROL MECHANISM UTILIZING PROGRAMMABLE MICROCODE REPEAT COUNTER

摘要

The microcode control mechanism includes a sequence counter (18) for supplying a sequence of numbers, a programmable logic array (17) responsive to the processor instruction and to the sequence of numbers for producing a sequence of microwords needed to execute the instruction, a repeat circuitry (30, 31) responsive to a predetermined microword produced by the programmable logic array (17) for setting the sequence counter (18) back to a count which is less than the current count for causing a selected portion of the microword sequence to be repeated, and a programmable repeat counter (92) for counting the number of times the selected portion is repeated and for disabling the repeating action after a selected number of repeats.