EMMS            Empty MMX State

EMMS                                                 CPU: MMX

        Logic    TAG word <- 0FFFFh

    The EMMS instruction sets the values of the floating-point tag word
    to empty (all ones). EMMS marks the registers as available, so they
    can subsequently be used by FPU instructions.

    If an FP instruction loads into one of the registers before it has
    been reset by EMMS, an FP stack overflow can occur, which results in
    an FP exception or incorrect result. 

    All other MMX instructions validate the entire FP tag word (all
    zeros).


    Note
    This instruction must be used to clear the MMX state at the end of
    all MMX routines/code blocks, and before calling other routines that
    may execute floating-point instructions.


    Opcode      Format
    0F 77       EMMS