Working of Central Processing Unit

Central Processing Unit

The Central Processing Unit (CPU; sometimes just called processor) is a machine that can execute computer programs. It is sometimes referred to as the brain of the computer.

There are four steps that nearly all CPUs use in their operation: fetch, decode, execute, and write back. The first step, fetch, involves retrieving an instruction from program memory. In the decode step, the instruction is broken up into parts that have significance to other portions of the CPU. During the execute step various portions of the CPU, such as the arithmetic logic unit (ALU) and the floating point unit (FPU) are connected so they can perform the desired operation. The final step, write back, simply writes back the results of the execute step to some form of

memory.