Ring reduction logic mechanism

Abstract From the Canadian patent

During the execution of an instruction by an execution unit, the instruction is stored in an instruction register the operand including its ring number is stored in a data register and the ring number developed by the Virtual Memory Management Unit is stored in a ring effective register. The instruction addresses a control store which stores a firmware word in a control store register. A firmware field is decoded to generate a plurality of ring control signals. The ring, numbers from the data and ring effective registers are compared and an effective ring number is generated. Depending on the states of the secure process signal the, ring control signals and the relative value of the ring …