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From: "Gerrit van Niekerk" <gerritvn AT gpvno DOT co DOT za>
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To: djgpp AT delorie DOT com
Date: Fri, 02 Nov 2007 11:35:43 +0200
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Subject: Re: PM interrupt handling - how to call old old ISR with slower rate than my new ISR
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On 1 Nov 2007 at 20:46, DJ Delorie wrote:

> 
> You need to use the non-chained hook, and call the old one via one of
> the other DPMI functions... "call real mode procedure with IRET frame"
> 
Just be warned: If you have a real-mode TSR that also hooked the 
timer interrupt and that enables interrupts or calls DOS even with all 
the pre-cautions to ensure DOS re-enterabilty, the system will silently crash
if you do the above! I have not found a way around this apart from avoiding
it.