Int 67 Fn 56  - Lim Ems 4.0 - Alter Page Map And Call                      [m]

   AH = 56h
   AL = subfunction
       00h physical page numbers provided by caller
       DX = handle
       DS:SI -> structure containing page map and call address
       01h segment addresses provided by caller
       DX = handle
       DS:SI -> structure containing page map and call address
       02h get page map stack space required

       Return: BX = stack space required

Return: (if successful, the target address is called.  Use a RETF to return
    and restore mapping context)
   AH = status (00h,80h,81h,83h,84h,8Ah,8Bh,8Fh) (see #3319)

See Also: AH=55h