In computing, an instruction register (IR) is the part of a CPU’s control unit that holds the instruction currently being executed or decoded. An instruction register is the part of a CPU’s control unit that holds the instruction currently being executed or decoded. The instruction register specifically holds the instruction and provides it to the instruction decoder circuit.
The Memory Address Register (MAR) is the CPU register that either stores the memory address from which data will be fetched from the CPU, or the address to which data will be sent and stored. It is a temporary storage component in the CPU(central processing unit) that temporarily stores the address (location) of the data sent by the memory unit until the instruction for the particular data is executed.
