FNSTCW            Store Control Word (No-wait)  Exception Flags: None

FNSTCW memory location

       Logic:      [memory location] . control word

     FNSTCW is the no-wait form of FSTCW. It stores the control word in a
     16-bit memory location. The FSTCW form checks for unmasked
     exceptions before storing the word, but the FNSTCW form does not.

     The control word stores all exception masks, the interrupt enable
     mask, and fields for precision control, rounding control, and
     infinity control.

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   Operands            Clocks         Bytes           Example
   FNSTCW memory16     12-18            4             FNSTCW CONTROL_WORD
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