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Date:	Thu, 7 Feb 2002 13:12:50 +0200 (IST)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender:	eliz AT is
To:	Martin Steuer <martinSteuer AT gmx DOT de>
cc:	djgpp AT delorie DOT com
Subject:	Re: Strange gdb behaviour
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On Thu, 7 Feb 2002, Martin Steuer wrote:

> int main()
> {
>   char key = 0;
>   while (key != 27)
>   {
> //  __asm__ __volatile__ ("sti");
>    if (kbhit()) key = getch();
>   }
>   return 0;
> }
> 
> The interrupts get disabled whenever I set a breakpoint somewhere, it can 
> be on EVERY line. If I uncomment the sti instruction it works.
> 
> The problem only occurs under pure dos, so I can imagine that it might be 
> the result of a problem in cwsdpmi too.

It's a known problem, due to the way CWSDPMI implements the Int 31h 
interface.  For details, read the discussion on djgpp-workers list whose 
subject is "GDB, DOS 6.22, CWSDPMI and Interrupts".  The message which 
started that discussion is here:

  http://www.delorie.com/djgpp/mail-archives/browse.cgi?p=djgpp-workers/1999/12/30/02:54:16

The only known work-around is to inject ``asm("sti")'' into your program 
from time to time.

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