INT 33H 0014H: Exchange Mouse Event Handler
Expects: AX 0014H
CX event mask (events which you want sent to your handler)
bit 0 = mouse movement (CX | 01H)
bit 1 = left button pressed (CX | 02H)
bit 2 = left button released (CX | 04H)
bit 3 = right button pressed (CX | 08H)
bit 4 = right button released (CX | 10H)
bit 5 = center button pressed (CX | 20H)
bit 6 = center button released (CX | 40H)
All events: CX = 007fH
ES:DX address of your event handler code
Returns: CX event mask of previous event handler
ES:DX address of the previously-installed event handler code
Info: This function works like INT 33H 000cH (which see for details).
The only difference is that upon return, you obtain the address
and event mask of the previously-installed event handler.
This provides a way to install an event handler temporarily; that
is, you can install one while performing a certain subroutine,
then restore the previous one when you exit that subroutine.
This also provides a way to chain event handlers. Install a
handler for all events, and if you get an event which you don't
really care about, pass it on to the previously-installed handler
(assuming its event mask shows that it expects the event).
Notes: INT 33H 0018H provides a flexible means for installing up to
three specialized-event handlers.
See Also: INT 33H: Mouse Support
Interrupts and BIOS Services