The part of the central processor of a computer in which simple arithmetic and logical operations are performed electronically. For example, the ALU can add, subtract, multiply, compare two numbers, or negate a number.
Computer
A portion of the central processor that generally forms functions of (usually) two input values and produces a single output result. These functions usually consist of the common arithmetic operations, the common logic operations, and shift operations. Associated with the ALU is a condition-code register that holds certain properties of the result of the most recent ALU operation (see alsoprogram status word).