Abstract
This paper describes the design of algorithms for unidirectional division. Rather than the conventional, restoring or nonrestoring, divisions which require both subtraction and addition operations, alternately, during the process of division, the proposed method needs only one direction, either subtraction or addition, but not both, during the process of the division. If both operands, dividend and divisor, are positive or negative, only subtraction is used. However, if one is positive and the other negative, only addition is applied. This method can skip zero bits in dividend, and consequently the number of additions/ subtractions is expected to be less than conventional division, about (3/5)n compared to 3/2n (or n if MUXes are used) for restoring or to n for nonrestoring. In addition, unidirectional division can be processed in parallel or in semi-parallel, if the bit length of the dividend is long enough. This method is also easily extended to apply to two's complement divisions. The conversion of th e quotient to binary is not required for the proposed method, (in which nonrestoring division is necessarily converted back to binary code in order to match other operations, because the resulting quotient is expressed by signed-digit code).