PCMPGTD         Packed Compare Greater Than, Doubleword

PCMPGTD destination, source                          CPU: MMX

        Logic   if mm(31..0)  > mm/m64(31..0)
                     mm(31..0)  <- 0FFFFFFFFh
                else mm(31..0)  <- 0
                endif
                if mm(63..32) > mm/m64(63..32)
                     mm(63..32) <- 0FFFFFFFFh
                else mm(63..32) <- 0
                endif

    PCMPGTD compares the signed doublewords in the destination operand
    to the signed doublewords in the source operand. If the signed data
    elements in destination are greater than those in the source operand,
    the corresponding data element in the destination operand is set to
    all ones. Otherwise, it is set to all zeros. 

    The destination operand is an MMX register. The source operand can
    either be an MMX register or a 64-bit memory operand.


    Opcode      Format
    0F 66 /r    PCMPGTD mm, mm/m64