The logic circuit in a central processing unit that computes common logical and arithmetic operations involving one or two fixed-width operands, producing a fixed-width result. Also known as an integer unit (IU), it has control inputs that determine which operation is to be performed, and also reads and writes status bits that record additional information, such as carry-in and carry-out, or whether a result is positive, zero, or negative. Modern superscalar processors have multiple ALUs running in parallel.