Invention Grant
- Patent Title: Fast floating point compare with slower backup for corner cases
- Patent Title (中): 快速浮点与较慢的备份角落比较
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Application No.: US12255968Application Date: 2008-10-22
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Publication No.: US08407275B2Publication Date: 2013-03-26
- Inventor: Maarten J. Boersma , Michael Kroener , Silvia M. Mueller , Jochen Preiss
- Applicant: Maarten J. Boersma , Michael Kroener , Silvia M. Mueller , Jochen Preiss
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agency: Cantor Colburn LLP
- Agent Randall Bluestone
- Main IPC: G06F7/02
- IPC: G06F7/02

Abstract:
A floating point processor unit executes a floating point compare instruction with two operands of the same or different precision by comparing the two operands in integer format, which speeds up the execution of the floating point compare instruction significantly. The floating point processor now executes the floating point compare instruction at least twice as fast or faster (e.g., two clock cycles instead of five clock cycles in the prior art) for nearly most operand cases (e.g., 99% of all cases). Only the rare corner cases require additional operations on one of the operands and thus require additional cycles of execution time because the integer compare operation will not work for these corner cases. This is due to the fact that one operand is a single precision subnormal number in an unnormalized representation (i.e., has two representations) and the other operand is in the SP subnormal range such that the integer compare operation will fail.
Public/Granted literature
- US20100100713A1 FAST FLOATING POINT COMPARE WITH SLOWER BACKUP FOR CORNER CASES Public/Granted day:2010-04-22
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