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From: kulokari@cc.helsinki.fi (HANNU, HYLK, PUH. 90/7084283)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Mouse (int 33h) problems
Message-ID: <1563@cc.helsinki.fi>
Date: 27 Jan 89 12:04:16 GMT
References: <68532MRS120@PSUVM>
Organization: University of Helsinki Computing Centre
Lines: 20

In article <68532MRS120@PSUVM>, MRS120@PSUVM.BITNET writes:
> I am trying to interface a Turbo Pascal 4.0 program with the Microsoft
> Mouse driver & am having some difficulties.  My problem boils down to
> the following:
..
>      RETurn control to the mouse interrupt routine.  Nothing happens
>      & the system hangs.  Tracing shows the system returning to some
>      empty segment of memory (ie: Definitely the wrong place).

The "Mouse Interrupt Routine" is interrupt routine in name only.
Actually, it is called by the mouse driver by FAR call, and should
exit by FAR RET, not IRET. If you exit by IRET, one word too many
is popped (the flags, which aren't there).

If you insist on using Turbo interrupt procedure, you must insert
some inline code at the end. The code should pop the saved registers
and do a far return.

Hannu Kulokari
Computing Centre, University of Helsinki, Finland