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From: janices@tekig5.UUCP (Janice Singer)
Newsgroups: net.micro.pc
Subject: Info about Interrupts
Message-ID: <55@tekig5.UUCP>
Date: Tue, 26-Mar-85 14:50:54 EST
Article-I.D.: tekig5.55
Posted: Tue Mar 26 14:50:54 1985
Date-Received: Thu, 28-Mar-85 23:54:16 EST
Organization: Tektronix, Beaverton OR
Lines: 23

Help!

I'm trying to write my own Interrupt Handler for a IBM PC/AT running 3.0
DOS.  O'kay, so first I load the interrupt vector with INT 21H - 25H,
then I execute INT 21H - 31H to keep the program resident (AL = 00H).
This all seems to work fine.  The problem is that when I try to use the
interrupt (At this point, I am just redefining PrtSc by resetting INT
05H), the system dies.  Is it because from within my handler I also call 
INT 21H.  I thought that a interrupt handler could safely use Function 
Calls 0-12H.  Is this not true?

Also, is there any good technical reference out there that will help me
find this stuff out.  I already have the DOS and IBM technical
reference.  

Since I am new to the net, if this sort of question is not of general
interest, please reply to me directly.

JANICE SINGER.

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