From:	"Joe Hagen" <jdhagen AT itis DOT com>
Newsgroups:	comp.os.msdos.apps,comp.os.msdos.djgpp,comp.os.msdos.misc,comp.os.msdos.programmer,microsoft.public.win95.msdosapps
Subject:	Re: Error running a program in dos box (win95)
Date:	Mon, 16 Feb 1998 23:21:53 -0600
Organization:	IntraNet Inc: Madison, Wisconsin's ISP
Lines:	55
Message-ID:	<6cb6u0$t73$1@news.itis.com>
References:	<6ca60c$g8c$1 AT isn DOT dac DOT neu DOT edu>
NNTP-Posting-Host:	a14-15.itis.com
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Salehi,

   I've recently experienced this runtime error in a
program used for copying image files to & from floppy.

   I disassembled the program, and found it was crashing
while calculating a time scaler for the machine by
incrementing a variable to count the duration of 1 BIOS
clock tick.

The calculation causes a Divide Overflow.  Based on the
runtime error (200) and the offset address (91H), I would
suspect texcad was written in Turbo Pascal.

Here's some "C" pseduocode:

        short counts_per_tick;
         long count=0;

        while (bios tick count is unchanged)
            ++count;

        counts_per_tick = count / 55;   // each tick is 54.9ms

On my machine, a 266 PII, the "count" value typically reaches
a value of over 4000000, which means the result won't fit
into a 16-bit value.

I had to patch the executable to make it usable, by substi-
tuting the max result, FFFFH, the program would not crash.

I also encountered this problem with Procomm version 2.x
for DOS.  The program would simply abort with Divde Overflow,
and exit back to the DOS prompt.  By patching the executable,
I was able to make it function on the faster machine.

Joe
jdhagen AT itis DOT com

salehi AT omid DOT cdsp DOT neu DOT edu wrote in message <6ca60c$g8c$1 AT isn DOT dac DOT neu DOT edu>...
>I have recently moved my programs from an old pc (running win95) to a new
pc
>9again win95). Among these programs obe dos program called texcad behaves
>strangely and when I start it gives me the error message:
>
>Runtime error 200 at 1235:0091.
>
>Is anyone familiar with this error type and how to prevent it. Please
respond
>by email.
>
>Thanks,
>

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