What is the role of IR and PC?
Instruction Register (IR) having the instruction being implemented. Its output is available to the control circuits, which make the timing signals for controlling the processing circuits required to implement the instructions. The Program Counter (PC) register keeps track of the execution of the program. It having the memory address of the instruction currently being implemented. During the execution of the current instruction, the contents of the PC are updated to correspond to the address of the next instructions to be implemented.