INT 2F - DESQview v2.26+ External Device Interface - ADD PROCESS
        AX = DE04h
        BX = mapping context of new process
        DX = handle of process
Return: nothing
Notes:  XMS XDI handler (installed by default) allocates a 22-byte record
          (see below) from "common" memory to control access to XMS memory
        all DOS, BIOS, and DV API calls are valid in handler
        driver should pass this call to previous handler after processing it
SeeAlso: AX=DE06h,INT 15/AX=5401h

Format of XMS XDI structure:
Offset  Size    Description
 00h    DWORD   pointer to 10-byte record???
 04h    DWORD   pointer to next XMS XDI structure
 08h    WORD    mapping context
 0Ah    BYTE    ???
 0Bh  5 BYTEs   XMS entry point to return for INT 2F/AX=4310h
                (FAR jump to next field)
 10h  6 BYTEs   FAR handler for XMS driver entry point
                (consists of a FAR CALL followed by RETF)