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FCLEX

Clears the floating-point exception control word and the floating-point exception status word.

The following table covers the supported source and destinations:

DO NOT support LOCK

This instruction is available in both 64-bit mode and compatibility mode. It specifically targets the x87 FPU state regardless of the current execution mode.

To avoid unexpected behavior in multitasking environments, ensure the FPU state is saved via FSAVE or FXSAVE before executing FCLEX if the previous status flags are required for error handling.