Very high radix square root with prescaling and rounding and a combined division/square root unit

An algorithm for square root with prescaling and selection by rounding is d eveloped and combined with a similar scheme for division. Since division is usually more frequent than square root, the main concern of the combined i mplementation is to maintain the low execution time of division, while acce pting a somewhat larger execution time for square root. The algorithm is pr esented in detail, including the mathematical development of bounds for the first square-root digit and for the scaling factor. The proposed implement ation is described, evaluated and compared with other combined div/sqrt uni ts. The comparisons show that the proposed scheme potentially produces a si gnificant speed-up for division, whereas, for square root, the speed-up is small.