Get expanded memory hardware information

        Entry:
          AH = 59h
          AL = subfunction
                00h get hardware configuration array
                    ES:DI = pointer to buffer to be filled with array
                01h get unallocated raw page count
        Return:
          BX = unallocated raw pages (subfunction 01h)
          DX = total raw pages (subfunction 01h)
          AH = status
            00h successful
            80h internal error
            81h hardware failure
            84h undefined function requested
            8Fh undefined subfunction
            A4h access denied by operating system

        Note: Subfunction 00h is for use by operating systems only,
              and can be enabled or disabled at any time by the
              operating system.