GET VENDOR SPECIFIC API ENTRY POINT


            Some DOS extenders provide extensions to the standard set of
            DPMI calls.   This  call is  used to obtain an address which
            must be  called to  use the  extensions.   The caller points
            DS:(E)SI to  a null  terminated string  that  specifies  the
            vendor name  or some  other unique  identifier to obtain the
            specific extension entry point.

            To Call

                 AX = 0A00h
                 DS:(E)SI = Pointer to null terminated string

            Returns

                 If function was successful:
                 Carry flag is clear
                 ES:(E)DI = Extended API entry point
                 DS, FS,  GS, EAX,  EBX, ECX,  EDX, ESI,  and EBP may be
            modified

                 If function was not successful:
                 Carry flag is set

            Programmer's Notes

                 o    Execute a far call to call the API entry point.
                 o    All extended  API parameters  are specified by the
                      vendor.
                 o    The string comparison used to return the API entry
                      point is case sensitive.