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Volume 4: Base IA-32 Instruction Reference
WAIT/FWAIT—Wait
Description
Causes the processor to check for and handle pending unmasked floating-point
exceptions before proceeding. (FWAIT is an alternate mnemonic for the WAIT).
This instruction is useful for synchronizing exceptions in critical sections of code. Coding
a WAIT instruction after a floating-point instruction insures that any unmasked
floating-point exceptions the instruction may raise are handled before the processor
can modify the instruction’s results.
Operation
CheckPendingUnmaskedFloatingPointExceptions;
FPU Flags Affected
The C0, C1, C2, and C3 flags are undefined.
Floating-point Exceptions
None.
Protected Mode Exceptions
#NM
MP and TS in CR0 is set.
Real Address Mode Exceptions
#NM
MP and TS in CR0 is set.
Virtual 8086 Mode Exceptions
#NM
MP and TS in CR0 is set.
Opcode
Instruction
Description
9B
WAIT
Check pending unmasked floating-point exceptions.
9B
FWAIT
Check pending unmasked floating-point exceptions.
Summary of Contents for ITANIUM ARCHITECTURE
Page 1: ......
Page 7: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 199: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 352: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 589: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 590: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 591: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 603: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...
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