A 1.5 GFLOPS Reciprocal Unit for Computer Graphics

The reciprocal operation 1/d is a frequent operation performed in graphics processors (GPUs). In this work, we present the design of a radix-16 reciprocal unit based on the algorithm combining the traditional digit-by-digit algorithm and the approximation of the reciprocal by one Newton-Raphson iteration. We design a fully pipelined single-precision unit to be used in GPUs. The results of the implementation show that the proposed unit can sustain a higher throughput than that of a unit implementing the normal Newton-Raphson approximation, and its area is smaller.