Dividers:Even Higher Radix Dividers with a Multiplier.

Even Higher Radix Dividers with a Multiplier

Division with even higher radix, say radix-28, based on the iteration of calculating Rj by r · Rj –1 – qj · Y, requires a multiplier for the generation of the divisor multiple qj · Y. This multiplier is also used for prescaling the divisor very close to 1, so that the quotient digit is produced by truncation or rounding of the shifted partial remainder to the left of the radix point.

Many variations of the method are feasible, depending on the choice of the radix, the quotient-digit set, the representation of the partial remainder (non-redundant or redundant), quotient-digit selection (by truncation or rounding), calculation of the scaling factor, and scaling. The scaling factor can be calculated by any method that produces an approximation of the reciprocal of the divisor. Direct approximation by table look-up and linear interpolation by table look-up followed by multiply-addition are examples. There are three ways of performing scaling: scaling the divisor and the dividend, scaling the divisor and the quotient, and scaling the partial remainder in each iteration. A version of this method is realized in a math-coprocessor [1].