Date: Sun, 4 May 1997 13:34:10 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Michael Mauch <mauch AT uni-duisburg DOT de>
cc: djgpp AT delorie DOT com
Subject: Re: testing uclock()
In-Reply-To: <3364e262.1961163@news.uni-duisburg.de>
Message-ID: <Pine.SUN.3.91.970504133340.9215E-100000@is>
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On Tue, 29 Apr 1997, Michael Mauch wrote:

> Oh, that's the problem then. Doesn't this mean that we can't use
> uclock() in a Win95 DOS window, because we don't know what mode that
> default mode is?

Yes, you shouldn't use `uclock' on Windows 95.

> On the other hand: isn't it possible that this default mode is just
> the same as the one set by the first call to uclock()? The
> difference between two consecutive calls to uclock() remains the
> same, even after that single negative difference.

No, you can't work with the default mode at all.  Under that mode, the
timer counter goes up and down twice during the 54 msec period, so you
cannot reliably compute the interval.

> I removed the first three outportb() calls from the uclock source
> code, and now I don't get any negative differences anymore.

I think that is specific to the time that your test program waited
between two calls to `uclock'.  Try different intervals and you will
see the problem again.