INT 2fH 16xxH: Enh386 Windows Services & Notifications

                                                     Compatibility: Win 3.0+ 
     See: 1600H (srvc: is enh386 windows installed?)
          1602H (srvc: get enh386 windows entry-point address)
          1605H (ntfy: windows is about to startup)
          1606H (ntfy: windows is about to terminate)
          1607H (ntfy: device call out)
          1608H (ntfy: windows initialization is finished)
          1609H (ntfy: windows is terminating)

          1680H (srvc: release time-slice)
          1681H (srvc: begin critical section)
          1682H (srvc: end critical section)
          1683H (srvc: get current VM ID)
          1684H (srvc: get VxD device API entry-point address)
          1685H (srvc: switch VMs and callback)
          1686H (srvc: detect INT 31h DPMI services)

   Notes: ■ These functions relate to Enhanced-Mode Windows.  They are
            fully-documented in the Windows Device Driver Kit (DDK) since
            they are usually used as means for a DOS-level device driver to
            communicate with Windows and Windows device drivers.

          ■ The services are tools that can be called by utilities, TSRs,
            and device drivers to access services provided by Windows.

          ■ The notifications represent INT 2fH fns that are invoked by
            Windows.  To receive these notifications, you are expected to
            chain into INT 2fH and watch for AX=16xxH.

See Also: INT 2fH: Multiplex Interrupt
          DPMI Services
          DOS Functions