CONTROL DEVICE FOR MICRO-INSTRUCTIONS RECORDED IN A MEMORY OF AN INFORMATION PROCESSING UNIT

摘要

A controller for microinstructions grouped into microprogram segments, each of which defines a base of a microprogram segment which is to be executed, includes a bank of addressable base registers. Each register in the bank stores an indication of a base in the memory. Registers in the bank are addressed so that the addressed register derives a signal indicative of the base address. Included are an address register for the memory and an output register for microinstructions read from the memory. The address and output registers respectively have outputs and inputs coupled to an address input and a read output of the memory. An adder has inputs responsive to the base indicating signal of the addressed register and to an output of the memory output register. The adder has an output coupled to an input of the address register. The output of the memory output register is coupled to an input of the means for addressing registers in the register bank to control which register of the base register bank is addressed.