INT 31 P - DPMI 0.9+ - GET VENDOR SPECIFIC API ENTRY POINT
        AX = 0A00h
        DS:SI / DS:ESI -> case-sensitive ASCIZ vendor name or identifier
Return: CF clear if successful
            ES:DI / ES:EDI -> FAR extended API entry point
            DS, FS, GS, EAX, EBX, ECX, EDX, ESI, EBP destroyed
        CF set on error
            AX = error code (DPMI 1.0+) (8001h) (see AX=0000h)
Notes:  extended API parameters are vendor-specific
        DPMI 1.0+ supports this function solely for backward compatibility; use
          INT 2F/AX=168Ah instead