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AssigneeInternational Business Machines Corporation
InventorsMichael F. Cowlishaw, Eric M. Schwarz, Ronald M. Smith, Sr., Phil C. Yeh
Estimating the term…
A round-for-reround mode (preferably in a BID encoded Decimal format) of a floating point instruction prepares a result for later rounding to a variable number of digits by detecting that the least significant digit may be a 0, and if so changing it to 1 when the trailing digits are not all 0. A subsequent reround instruction is then able to round the result to any number of digits at least 2 fewer than the number of digits of the result. An optional embodiment saves a tag indicating the fact that the low order digit of the result is 0 or 5 if the trailing bits are non-zero in a tag field rather than modify the result. Another optional embodiment also saves a half-way-and-above indicator when the trailing digits represent a decimal with a most significant digit having a value of 5. An optional subsequent reround instruction is able to round the result to any number of digits fewer or equal to the number of digits of the result using the saved tags.
A computer implemented method for rounding a decimal floating point number to a lesser precision in a computer processor, the method comprising:
A computer system for rounding a decimal floating point number to a lesser precision, the computer system comprising:
A computer program product for rounding a decimal floating point number to a lesser precision in a computer processor, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program instructions executable by a computer processor to cause the computer processor to perform a method comprising:
Dependencies are inferred from the claim text.