Introduction
A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary processor in a given computer.[1][2] Its electronic circuitry executes instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations.[3][4][5] This role contrasts with that of external components, such as main memory and I/O circuitry,[6] and specialized coprocessors such as graphics processing units (GPUs).