INT 31H 0509H: Map Conventional Memory in Memory Block

                                         Compatibility: DPMI [optional] 1.0+ 
 Expects: AX    0508H
          ESI   memory block handle (as obtained via INT 31H 0504H)
          EBX   base offset of page(s) to map
          ECX   number of pages
          EDX   physical address of conventional memory (page-aligned)
 Returns: CF    NC (clear) if successful; else AX = DPMI Error Code
    Info: This aliases linear addresses below the 1 MB boundary into the
          linear addresses of a block allocated via INT 31H 0504H.

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