INT 31H 0002H: Segment to Descriptor

                                                    Compatibility: DPMI 0.9+ 
 Expects: AX    0002H
          BX    real-mode segment address
 Returns: CF    NC (clear) if successful; else AX = DPMI Error Code
          AX    selector to access 64K starting at the real-mode paragraph
    Info: Maps a real-mode segment address to a protected-mode selector.

          Applications can use this in order to access segments such as
          0040:xxxx (BIOS Data Area) and b800:xxxx (CGA/text-mode memory).

          You may prefer to use INT 31H 0000H to allocate a descriptor and
          then use INT 31H 0007H to point it to various real-mode

See Also: DPMI API
          INT 2fH: Multiplex Interrupt
          DOS Functions