Int 2F Fn 1684  - MS Windows - Get Device API Entry Point                  [W]

   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.

See Also: AX=1683h

Values for VxD ID:
Value  Name    CallOut V86 PM  Description
 01h   VMM     N  N    Virtual Machine Manager
 02h   Debug
 03h   VPICD       Y  Y    Virtual Prog. Interrupt Controller (PIC) Device
 04h   VDMAD       N  N    Virtual Direct Memory Access (DMA) Device
 05h   VTD     Y  Y    Virtual Timer Device
 06h   V86MMGR     N  N    Virtual 8086 Mode Device
 07h   PageSwap    N  N    Paging Device
 08h   Parity      N  N    Parity-check trapper
 09h   Reboot      N  Y    Ctrl-Alt-Del handler
 0Ah   VDD     N  Y    Virtual Display Device (GRABBER)
 0Bh   VSD     N  N    Virtual Sound Device
 0Ch   VMD   Y Y  Y    Virtual Mouse Device
 0Dh   VKD     N  Y    Virtual Keyboard Device
 0Eh   VCD     N  Y    Virtual COMM Device
 0Fh   VPD         Virtual Printer Device
 10h   VHD         Virtual Hard Disk Device (Windows 3.0)
 10h   BLOCKDEV    N  N    Virtual Hard Disk Device (Windows 3.1)
 10h   IOS     N  Y    (Chicago)
 11h   VMCPD       Y  Y    Virtual Math CoProcessor Device
 12h   EBIOS       N  N    Reserve EBIOS page (e.g., on PS/2)
 13h   BIOSXLAT    N  N    Map ROM BIOS API between prot & V86 mode
 14h   VNETBIOS  Y N  N    Virtual NetBIOS Device
 15h   DOSMGR      Y  N
 16h   WINLOAD
 17h   SHELL       N  Y
 18h   VMPOLL      N  N
 19h   VPROD
 1Ah   DOSNET      N  N    assures network integrity across VMs
 1Ah   VNETWARE    Y  Y    Novell NetWare DOSNET replacement
 1Bh   VFD     N  N    Virtual Floppy Device
 1Ch   VDD2            Secondary display adapter
 1Ch   LoadHi      N  N    Netroom LoadHi Device (RMLODHI.VXD)
 1Ch   LoadHi      N  N    386MAX LoadHi Device (386MAX.VXD)
 1Ch   LoadHi      N  N    Win386 LoadHi Device (EMM386.EXE)
 1Dh   WINDEBUG    N  Y
 1Dh   TDDebug     N  Y
 1Eh   TSRLoad         TSR instance utility
 1Fh   BiosHook        BIOS interrupt hooker VxD
 20h   Int13      N    N  N
 21h   PageFile    N  Y    Paging File device
 22h   SCSI
 23h   MCA_POS
 24h   SCSIFD          SCSI FastDisk device
 25h   VPEND           Pen device
 26h   APM         Advanced Power Management
 27h   VXDLDR      Y  Y    (Chicago)
 2Ah   VWIN32      N  Y    (Chicago)
 2Bh   VCOMM       Y  Y    (Chicago)
 30h   MACH32      N  Y    ATI Mach32 video card
 33h   CONFIGMG    Y  Y    (Chicago)
 33h   EDOS        N  N    Windows DOS Box Enhancer by Mom's Software
 36h   VFBACKUP    Y  Y    (Chicago)
 38h   VCOND       Y  Y    (Chicago)
 51h   ISAPNP      N  N
 8Dh   ESDI_506    N  N    (Chicago)
 90h   voltrack    N  N
 FDh   FAKEIDE     N  N    (Chicago)
0102h  CV1     N  N    Microsoft C/C++ 7.00+ CodeView for Windows
0200h  VIPX        Y  Y    NetWare Virtual IPX Driver
0201h  VNWLSERV    N  N    NetWare Lite 1.1 Server (SERVER.EXE)
0202h  WINICE      Y  Y    SoftICE/W
0203h  VCLIENT     N  Y    NetWare Lite 1.1+ Client
0205h  VCAFT       N  N    Novell Virtual CAFT Driver (LANalyzer for Win)
0206h  VTXRX       N  N    Novell Virtual TXRX Driver (LANalyzer for Win)
0234h  VCOMMUTE    Y  Y    PC Tools Commute
0442h  VTDAPI      N  Y    MMSys Win386 VTAPI Device
0444h  VADMAD          Autoinitialize DMA (Windows 3.0)
0445h  VSBD        Y  Y    WinResKit: Sound Blaster Device
0460h  UNIMODEM    N  Y
0483h  VSHARE      N  N    Windows for Workgroups Virtual SHARE
0484h  IFSMgr      Y  N    (Chicago) installable file system manager
0486h  VFAT        Y  Y    (Chicago)
048Bh  VCACHE      Y  Y
1021h  VMB     Y  Y    Microsoft C/C++ 7.00 WXSRVR
1022h  Vpfd        Y  Y    Microsoft C/C++ 7.00
1025h  MMD     Y  Y    Microsoft C/C++ 8.00, Visual C/C++ 1.00
21EAh  VADLIBWD    N  Y    Adlib Waveform Driver by John Ridges
2200h  VFINTD      Y  Y    Norton VFINTD (Norton Desktop)
2402h  ZMAX        N  N    Qualitas 386MAX v7 DOSMAX handler
24A0h  VNSS        N  Y    Norton Screen Saver (Norton Desktop)
24A1h  VNDWD       Y  Y    Norton VNDWD Device (Norton Desktop)
2640h  VASBID      N  Y    WinResKit: Artisoft Sounding Board Device
2860h  COMMTASK   N    N  Y    Windows 386-mode preemptive tasker by James
               A. Kenemuth of Interabang Computing
28C0h  VXD    N    Y  Y    Generic VxD for real and protected mode by
               Andrew Schulman in MSJ February 1993
292Dh  VSBPD       Y  Y    Sound Blaster Pro
3098h  VstlthD    N    N  N    for QEMM Stealth ROM mode
310eh  WPS     N  N    MS DevNet CD-ROM: Windows Process Status
7FE0h  VWFD       N    Y  Y    ??? by Neil Sandlin of Microsoft
7FE1h  VWATCHD    N    Y  Y    basic driver w/ no functionality except tracing
               by Keith Jin of Microsoft PSS
7FE5h  VFINTD     N    Y  Y    Virtual Floppy Interrupt trapper by Neil
               Sandlin of Microsoft
7FE7h  VMPAGES    N    Y  Y    demonstration of exporting VxD services, by
               Neil Sandlin of Microsoft
7FE9h  VIdleD     N    N  N    demonstration of Call_When_Idle function, by
               Bernie McIlroy of Microsoft
7FEBh  VMIOD      N    N  N    Virtual Monitor I/O Traffic Device, by Neil
               Sandlin of Microsoft
7FEDh  VMIRQD     N    N  N    Virtual Monitor IRQ Traffic Device, by Neil
               Sandlin of Microsoft

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.  Naturally, this scheme has not
   been adhered to since there are now more than 32 different VxDs.

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

Call VADMAD entry point with:
   DX = operation
       0000h set VADMAD mode
       AX = desired mode
       0001h set VADMAD channel
       AX = desired channel

Note:  after setting mode/channel, start the DMA operation with an OUT to
     I/O port 0Bh (channels 0-3) or D6h (channels 4-7)