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FCOMI           Compare real and set EFLAGS          Exceptions: I D
FCOMIP          Compare real, set EFLAGS, and pop    C3 C2 C1 C0: - - * -
                                                     FPU: PPro+
FCOMI destination, source
FCOMIP destination, source

        Logic   ; FCOMI dest, src       ; FCOMIP dest, src
                CMP ST, ST(src)         CMP ST, ST(src)
                determine ZF,PF,CF      determine ZF,PF,CF
                                        POP ST

    Compares the contents of register ST(0) and ST(i) and sets the
    status flags ZF, PF, and CF in the EFLAGS register according to the
    results.
    The sign of zero is ignored for comparisons, so that -0.0 = +0.0.

                ZF PF CF
                0  0  0  ST > ST(i)
                0  0  1  ST < ST(i)
                1  0  0  ST = ST(i)
                1  1  1  Unordered

    The FCOMI/FCOMIP instructions perform the same operation as the
    FUCOMI/FUCOMIP instructions. The only difference is how they handle
    QNaN operands. The FCOMI/FCOMIP instructions set the status flags to
    unordered and generate an invalid-arithmetic-operand exception (#IA)
    when either or both of the operands is a NaN value (SNaN or QNaN) or
    is in an unsupported format.

    The FUCOMI/FUCOMIP instructions perform the same operation as the
    FCOMI/FCOMIP instructions, except that they do not generate an
    invalid-arithmetic-operand exception for QNaNs.


    If invalid-operation exception is unmasked, the flags are not set if
    the invalid-arithmetic-operand exception is generated.


    Opcode      Format
    DB F0 + i   FCOMI ST, ST(i)
    DF F0 + i   FCOMIP ST, ST(i)
    DB E8 + i   FUCOMI ST, ST(i)
    DF E8 + i   FUCOMIP ST, ST(i)


    Timing
    ??