| 摘要 |
A logarithm determining method for use in a digital processor is provided. The method is for converting an input number x into a logarithm L by a base b. The logarithm L includes an integer part In and a mantissa part Ma. The method represents numbers in a fixed-point format. The method comprises the steps of: designating a number of digits of precision k for said mantissa part Ma; creating a plurality of reference tables based on said base b, wherein a number of said plurality of reference tables is equal to said number of digits of precision k and an m-th reference table is for evaluating an m-th digit to the right of the decimal point of said mantissa part Ma; calculating said integer part In; and searching in said plurality of reference tables sequentially to obtain a values from a first to a k-th digit to the right of the decimal point of said mantissa part Ma.
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