FLDENV          Load environment state               Exceptions: None
                                                     C3 C2 C1 C0: * * * *
FLDENV source

        Logic   FPU environment ← source

    FLDENV reloads the FPU environment from source, which must contain a
    new control word, status word, tag word, and error block. Usually,
    this data has been written by a previous FSTENV instruction.


    Note
    FLDENV should be executed in the same operating mode as the
    corresponding FSTENV or FNSTENV.
    If the environment image contains an unmasked exception, loading it
    will produce a floating-point error condition.


    Opcode      Format
    D9 /4       FLDENV m14byte  ; 16-bit code segment
    D9 /4       FLDENV m28byte  ; 32-bit code segment


    Timing
    Operand       8087         287        387      486     Pentium
    mem         (35-45)+EA    35-45       71      44/34    37/32-33 NP

                Cycles for real mode/protected mode