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From: bobb@vice.ICO.TEK.COM (Bob Beauchaine)
Newsgroups: comp.lang.pascal
Subject: Re: How to detect MS Mouse driver
Message-ID: <6405@vice.ICO.TEK.COM>
Date: 29 Nov 90 23:10:11 GMT
References: <25098@adm.brl.mil> <1990Nov29.141927.243@maytag.waterloo.edu>
Organization: Tektronix Inc., Beaverton, Or.
Lines: 23

In article <1990Nov29.141927.243@maytag.waterloo.edu> dmurdoch@watstat.waterloo.edu (Duncan Murdoch) writes:

>The test that Turbopower uses for the presence of an INT 33 ISR is just to
>look at the vector:  if it's not nil, they assume it's valid.
>

  The other possibility is that the INT 33 vector points to a vector in 
  low memory that is nothing but an IRET.  Just checking for a nil 
  vector won't guarantee that a mouse driver is/is not present.

  Something like this will check both:

  const IRET = $CF;

  var mouse_vec : pointer absolute $0000:0033;
      mouse_present : boolean;

      mousepresent := not((longint(mouse_vec) = 0) or 
			 (word(mouse_vec^) = iret));


Bob Beauchaine
bobb@vice.ICO.TEK.COM