PUNPCKHDQ       Unpack (interleave) High-order Doublewords

PUNPCKHDQ destination, source                        CPU: MMX

        Logic   mm(31..0)  <- mm(63..32)
                mm(63..32) <- mm/m64(63..32)
    
    PUNPCKHDQ interleaves the high-order doubleword of the source
    operand and the high-order doubleword of the destination operand
    and writes them to the destination.

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

    When unpacking from a memory operand, the full 64-bit operand is
    accessed from memory. PUNPCKHDQ uses only the high-order 32 bits.


    Opcode      Format
    0F 6A /r    PUNPCKHDQ mm, mm/m64