Invention Grant
- Patent Title: Rounding floating point division results
- Patent Title (中): 舍入浮点分割结果
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Application No.: US11330692Application Date: 2006-01-12
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Publication No.: US07752250B2Publication Date: 2010-07-06
- Inventor: Charles David Wait
- Applicant: Charles David Wait
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agent Karuna Ojanen; Robert R. Williams
- Main IPC: G06F7/44
- IPC: G06F7/44 ; G06F7/38 ; G06F7/52

Abstract:
A method for determining the correct result and the correct guard and sticky bits to obtain a more accurate result in floating point divide operations is presented. An intermediate divide result or quotient is obtained from a multiply-add hardware pipeline of a floating point processor. Remainders are calculated using the floating point numbers divided, the unit of least precision, and the unit of least precision plus one to determine where the infinitely precise result is with respect to the digital representation of the estimated quotient. Evaluating these remainders and the initial floating point numbers and comparing their signs and magnitudes leads to a selection of one of three choices as the most accurate representation of the infinitely precise result as calculated in the inventive rounding method: the intermediate result minus the unit of least precision; the intermediate divide result; or the intermediate divide result plus the unit of least precision. Based on a rounding mode determined by the floating point operation, the correct guard and sticky bits are also determined and, which along with the most accurate intermediate divide result, are forwarded for accurate rounding in accordance with the IEEE standard for single and double precision floating point numbers.
Public/Granted literature
- US20070162535A1 Rounding floating point division results Public/Granted day:2007-07-12
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