Nicholson De Vos Webster & Elliott LLP
Digital signal processor having instruction set with an exponential function using reduced look-up table
A digital signal processor is provided having an instruction set with an exponential function that uses a reduced look-up table. The disclosed digital signal processor evaluates an exponential function for an input value, x, by decomposing the input value, x, to an integer part, N, a first fractional part, q1, larger than a specified value, x0, and a second fractional part, q2, smaller than the specified value, x0; computing 2qusing a polynomial approximation, such as a cubic approximation; obtaining 2qfrom a look-up table; and evaluating the exponential function for the input value, x, by multiplying 2q, 2qand 2N together. Look-up table entries have a fewer number of bits than a number of bits in the input value, x.
Intel Corporation
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additional inventional inventional
Jian-Guo Joseph Kameran Samer
Chen Williams Azadet Hijazi