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1. (WO2001033341) MECHANISM TO DETECT IEEE UNDERFLOW EXCEPTIONS ON SPECULATIVE FLOATING-POINT OPERATIONS

Pub. No.:    WO/2001/033341    International Application No.:    PCT/US2000/025490
Publication Date: Fri May 11 01:59:59 CEST 2001 International Filing Date: Fri Sep 15 01:59:59 CEST 2000
IPC: G06F 9/32
Applicants: INTEL CORPORATION
STORY, Shane
Inventors: STORY, Shane
Title: MECHANISM TO DETECT IEEE UNDERFLOW EXCEPTIONS ON SPECULATIVE FLOATING-POINT OPERATIONS
Abstract:
A mechanism is disclosed for detecting underflow conditions for speculative floating-point operations. A floating-point status register includes a status flag which is set when a result generated by a floating-point instruction is 'tiny'. The status flag is cleared, all exceptions are masked, and the instruction is executed speculatively. The 'tiny' exception flag is read to determine whether the speculatively executed instruction should raise an unmasked underflow exception. The exception may be raised if the processor reaches a point of registration associated with the instruction. The exception may be ignored if this point is not reached.