30-ns 55-b shared radix 2 division and square root using a self-timed circuit

A shared radix 2 division and square root implementation using a self-timed circuit is presented. The same execution time for division and square root is achieved by using an on-the-fly digit decoding and a root multiple generation technique. Most of the hardware is shared, and only several multiplexers are required to exchange a divisor multiple and a root multiple. Moreover, quotient selection logic is accelerated by a new algorithm using a 3-b carry propagation adder. The implementation of the shared division and square root unit is realized by assuming 0.3 μm CMOS technology. The wiring capacitance and other parasitic parameters are taken into account. The execution time of floating point 55-b full mantissa division and square root is expected to be less than 30 ns in the worst case of an input vector determined by an intensive circuit simulation