ABSTRACT
This chapter presents computer arithmetic for the three number representations of fixed-point, decimal, and floating-point. It describes four basic operations of addition, subtraction, multiplication, and division for each number representation. Fixed-point addition includes a low-speed ripple-carry adder and a high-speed carry lookahead adder that generates the carries between stages in parallel. Subtraction is simply an extension of addition and uses the adders previously designed with appropriate modifications. The chapter discusses fixed-point multiplication for the following four methods: sequential add-shift algorithm, bit-pair recoding, and planar array multiplication. Fixed-point division expounds on the restoring and nonrestoring division techniques. The chapter presents decimal addition and subtraction in which all bits of both digits are processed in parallel. Subtraction is accomplished by adding the rs complement of the subtrahend to the minuend. Finally, the chapter describes decimal multiplication and division using a table lookup method.
