| 摘要 |
An apparatus for computing an exponential function ax with an N radix computer where a represents a positive constant and where X is a variable. The apparatus includes an X register for storing X and a generator which sequentially generates the logarithmic value loga (1+N-k) or Nkxloga (1+N-k) for values of k raning from o to m. Subtracting apparatus is provided which, for each logarithmic value generated, repeatedly subtracts the logarithmic value from the contents of the X register and stores the remainder in the X register until the contents of the register are less than the logarithmic value. The number of such repeated subtractions performed for each logarithmic value generated is stored in a Z register. A data shifting and adding apparatus is provided which upon termination of the repeated subtractions, sets an initial value in the X register and performs a sequence wherein a value is stored in a Y register which corresponds to the contents of the X register, the contents of the Y register are shifted k number of digits and the shifted contents are added to the contents of the X register. Such sequence is performed once for each of the repeated subtractions which had previously occurred as determined by the contents of the Z register with the value of k used in each sequence corresponding to that value used in the corresponding subtraction. Upon termination of the sequences, the final contents of the X register correspond to the value ax.
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