INT 2F - Quarterdeck RPCI - GET QD HIMEM PRESENCE
        AX = D201h
        BX = 4849h ("HI")
        CX = 4D45h ("ME")
        DX = 4D51h ("MQ")
Return: BX = 4F4Bh ("OK")
        ES:DI -> HIMEM entry point
Note:   AH=D2h is the default multiplex number, but any value in the range
          D2h-FFh and then C0h-D1h may be used (see AX=D200h for details)
SeeAlso: AX=D200h,AX=D201h/BX=5145h

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