A processor is the logic circuitry that responds to and processes the basic instructions that drive a computer. The four primary functions of a processor are fetch, decode, execute and writeback.<br /><br /><br />The basic elements of a processor:<br /><br />The arithmetic logic unit (ALU), which carries out arithmetic and logic operations on the operands in instructions. <br /><br />The floating point unit (FPU), also known as a math coprocessor or numeric coprocessor, a specialized coprocessor that manipulates numbers more quickly than the basic microprocessor circuitry can.<br /><br />Registers, which hold instructions and other data. Registers supply operands to the ALU and store the results of operations.<br /><br />L1 and L2 cache memory. Their inclusion in the CPU saves time compared to having to get data from random access memory (RAM).<br /><br />Most processors today are multi-core, which means that the IC contains two or more processors for enhanced performance, reduced power consumption and more efficient simultaneous processing of multiple tasks (see: parallel processing). Multi-core set-ups are similar to having multiple, separate processors installed in the same computer, but because the processors are actually plugged into the same socket, the connection between them is faster. <br /><br />The term processor is used interchangeably with the term central processing unit (CPU), although strictly speaking, the CPU is not the only processor in a computer. The GPU (graphics processing unit) is the most notable example but the hard drive and other devices within a computer also perform some processing independently. Nevertheless, the term processor is generally understood to mean the CPU.<br /><br />The processor in a personal computer or embedded in small devices is often called a microprocessor. That term simply means that the processor's elements are contained on a single integrated circuitry (IC) chip.
