From: Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Access video memory.
Date: Sun, 15 Jun 1997 21:00:46 +0100
Organization: None
Distribution: world
Message-ID: <3xveYAAunEpzEwY6@talula.demon.co.uk>
References: <339FA3B7 DOT FFEBA26F AT sr DOT flashnet DOT it>
 <SexnzXARHbozEwmG AT talula DOT demon DOT co DOT uk> <5o00mc$853 AT freenet-news DOT carleton DOT ca>
NNTP-Posting-Host: talula.demon.co.uk
MIME-Version: 1.0
Lines: 19
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

Paul Derbyshire writes:
>> I found the only really stable solution was not to draw anything 
>> inside the mouse callback (I use int 0x33) at all! Instead, I just 
>> store the mouse position and set a flag in the callback function, and 
>> then later draw the pointer from my timer interrupt handler...
>
>I guess the difference is the timer interrupt, which *you* control, is
>less frequent than the mouse interrupt...and spaced further apart than 
>the execution time for the drawing handler?

Also, the timer interrupt uses my own reentrant IRQ wrapper, so it
doesn't matter how long the drawing takes, wheras the mouse uses an RMCB
created by the libc code (non-reentrant). And who knows if the mouse
driver itself is smart enough to deal with reentrancy?


--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
Beauty is a French phonetic corruption of a short cloth neck ornament.