INT 2F - MS WINDOWS - GET DEVICE API ENTRY POINT
        AX = 1684h
        BX = virtual device (VxD) ID (see below)
        ES:DI = 0000h:0000h
Return: ES:DI -> VxD API entry point, or 0:0 if the VxD does not support an API
Note:   some Windows enhanced-mode virtual devices provide services that
          applications can access.  For example, the Virtual Display Device
          (VDD) provides an API used in turn by WINOLDAP.

Values for VxD ID:
 01h    VMM             Virtual Machine Manager
 02h    Debug
 03h    VPICD           Virtual Prog. Interrupt Controller (PIC) Device
 04h    VDMAD           Virtual Direct Memory Access (DMA) Device
 05h    VTD             Virtual Timer Device
 06h    V86MMGR         Virtual 8086 Mode Device
 07h    PAGESWAP        Paging Device
 08h    Parity
 09h    Reboot
 0Ah    VDD             Virtual Display Device (GRABBER)
 0Bh    VSD             Virtual Sound Device
 0Ch    VMD             Virtual Mouse Device
 0Dh    VKD             Virtual Keyboard Device
 0Eh    VCD             Virtual COMM Device
 0Fh    VPD             Virtual Printer Device
 10h    VHD             Virtual Hard Disk Device
 11h    VMCPD
 12h    EBIOS           Reserve EBIOS page (e.g., on PS/2)
 13h    BIOSXLAT        Map ROM BIOS API between prot & V86 mode
 14h    VNETBIOS        Virtual NetBIOS Device
 15h    DOSMGR
 16h    WINLOAD
 17h    SHELL
 18h    VMPoll
 19h    VPROD
 1Ah    DOSNET          assures network integrity across VMs
 1Bh    VFD             Virtual Floppy Device
 1Ch    VDD2            Secondary display adapter
 1Dh    WINDEBUG
 1Eh    TSRLoad         TSR instance utility
Note:   The high bit of the VxD ID is reserved for future use. The
        next 10 bits are the OEM # which is assigned by Microsoft. The
        low 5 bits are the device number.

Call VTD.386 entry point with:
        AX = 0000h get VTD version number
            Return: AH = major version
                    AL = minor version
        AX = 0100h get current clock tick time
            Return: EDX:EAX = clock tick time in 840ns units since Windows was
                                started
        AX = 0101h get current system time in milliseconds
            Return: EAX = time in milliseconds that Windows has been running
        AX = 0102h get current virtual machine time
            Return: EAX = cumulative amount of time the virtual machine has
                        been active, in milliseconds
Note:   should only be called directly when TOOLHELP.DLL TimerCount() cannot
          be called