From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: [Q] mouse under DJGPP
Date:	Fri, 20 Dec 1996 19:28:02 +0000
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Distribution:	world
Message-ID:	<+QzMTHACjuuyEwH6@talula.demon.co.uk>
References:	<01bbee00$9e9eab70$65216dc2 AT parkview>
NNTP-Posting-Host:	talula.demon.co.uk
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Yeep writes:
>I want to use the mouse in a program.
>So I would use Int 33h.
>But this is a real mode interrupt and if I use it with __dpmi_int__ it
>would make my program *very* slow (at least accoring to various FAQ's).

I don't think that is a problem. Mouse interrupts aren't frequent enough
to cause trouble due to the mode switching overhead. Real mode <-> pmode
reflection is only an issue with things like high-frequency timer
interrupts or bulk data transfers to external devices.

>Or do I need to poll the Com-ports myself?

This is, IMHO, rather dangerous, since there are several different sorts
of mice around and they don't all use the same protocols. Early versions
of Allegro used to read the com ports directly (I still have the code if
you are interested) but it only worked with MS serial mice. I switched
to using int33, and haven't had any trouble with it...

/*
 *  Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
 *  Ghoti: 'gh' as in 'enough', 'o' as in 'women', and 'ti' as in 'nation'.
 */

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