Faithful powering computation using table look-up and a fused accumulation tree

Authors:
  • JBJ.D. Bruguera
    J.D. Bruguera
  • JMJ.M. Muller
    J.M. Muller
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Abstract
A method for the calculation of faithfully rounded single-precision floating-point powering (X/sup p/) is proposed in this paper. This method employs table look-up and a second-degree minimax approximation, which allows the employment of reduced size tables to store the coefficients from the polynomial approximation. A specialized squaring unit and a fused accumulation tree carry out with the computation of the quadratic polynomial. Both unfolded and pipelined architectures are presented, and the results of a pre-layout synthesis performed using CMOS 0.35 /spl mu/m technology are shown, achieving a 50% area reduction from linear approximation methods, and with improved speed over other second-degree approximation based algorithms. The pipelined architecture has a latency of three cycles and a throughput of one result per cycle.