A computer processor, also known as a microprocessor or central processing unit (CPU), is a component in a computer system that functions as the brains of a computer. It is mainly responsible for processing instructions of a computer program and carrying out computer operations.
The CPU has two main components, the arithmetic/logic unit and the control unit. The control unit directs other portions of the computer system to carry out or execute program instructions. The arithmetic/logic unit executes all the arithmetic and logical instructions.
The four core functions of the CPU are to fetch, decode, execute and store. The first thing the CPU does is to fetch the instruction from the program memory. It decodes the instruction, which is then moved to the arithmetic/logic unit.
The arithmetic/logic unit then executes the instruction. At this stage, the processor can do one of three things: perform mathematical operations, move date from one memory location to another or jump to a bunch of new instructions based on the decision it makes. Finally, the arithmetic/logic unit stores the output of the operation into the computer's memory.
The performance and speed of the CPU depends on the clock rate, which is the speed at which a processor executes instructions, and the instructions per clock.