From:	ovek AT arcticnet DOT no (Ove Kaaven)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Allegro perspective-correct texture mapping
Date:	Tue, 04 Mar 1997 22:04:42 GMT
Organization:	Vplan Programvare AS
Lines:	33
Message-ID:	<5fi6a1$1ds$1@troll.powertech.no>
References:	<Pine DOT SUN DOT 3 DOT 91 DOT 970304134700 DOT 12059M-100000 AT is>
NNTP-Posting-Host:	alwayscold.darkness.arcticnet.no
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:

>On Mon, 3 Mar 1997, Ove Kaaven wrote:

>> [some irrelevant selectors]

>Bad judgement, IMHO.  You should never omit parts of the traceback,
>because they might give people here vital clues about the true nature
>of your problem.

There were no clues there; remember, this was a FPE, not GPF or PF; it
was within Allegro's domain, and did work most of the time; if there
were, I would have spotted it, since I had spent much of the time with
my code debugging every other cause for such crashes. And most
significantly, all the selectors pointed to the same memory area, as
they should. (Except gs, but that's not used in (those parts of)
Allegro)

>> I realize that this is probably a floating-point overflow, but is
>> there a good way around it?

>I suggest you first verify that the problem is indeed an overflow (it
>might be some other FP-related trouble, like passing an invalid
>argument to a math function).

Well, I had already verified the arguments. However, I got curious and
decided to recompile Allegro with the -g switch (to find out more),
and surprisingly, I couldn't reproduce the bug. It was gone.

My best guess is that I forgot to remove Allegro 2.2 beta object files
before I upgraded to 2.2... sorry to bother you for that silliness.

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