Intel 253666-024US - Manual (Page 348)

3-302 Vol. 2A FCLEX/FNCLEX—Clear Exceptions
INSTRUCTION SET REFERENCE, A-M
FPU Flags Affected
The PE, UE, OE, ZE, DE, IE, ES, SF, and B flags in the FPU status word are cleared.
The C0, C1, C2, and C3 flags are undefined.
Floating-Point Exceptions
None.
Protected Mode Exceptions
#NM CR0.EM[bit 2] or CR0.TS[bit 3] = 1.
#UD If the LOCK prefix is used.
Real-Address Mode Exceptions
Same exceptions as in protected mode.
Virtual-8086 Mode Exceptions
Same exceptions as in protected mode.
Compatibility Mode Exceptions
Same exceptions as in protected mode.
64-Bit Mode Exceptions
Same exceptions as in protected mode.