INT 2fH 4004H: Exit Critical Section

                                                      Compatibility: Win 3.x 
 Expects: AX    4004H
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 Returns: none
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    Info: After a previous call to INT 2fH 4003H (enter critical section),
          you should use this fn to signal the end of the critical session.

          If the VDD has been delaying an update to the video registers, it
          will perform it immediately upon receipt of this call.

          Calls to this fn without a preceding call to INT 2fH 4003H are
          ignored by the VDD.

See Also: INT 2fH 40xxH: Virtual Display Driver Functions
          INT 2fH: Multiplex Interrupt
          DOS Functions
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