Hardware interrupt mappings?

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#6234

From: Duncan Murdoch
Date: Wed, 30 Dec 1992 23:14

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In a standard PC in real mode, IRQs 0 to 7 are serviced by INTs 08 to 0F, and
IRQs 8 to 15 are serviced by INTs 70 to 77.  However, these mappings are 
changeable, and some multitaskers (e.g. Desqview) do change them.

If I want to install a handler for any of these hardware interrupts, should 
I use the original INT assignment, and assume that the multitasker will pass
the interrupt to me if it matters, or should I try to figure out what the 
true assignment is?  Is there any general sequence to go through to figure 
out the true assignment?

What I'm thinking of doing is writing a little TSR that preserves the 
386 extended registers across hardware interrupts.  This is necessary, since 
there's a lot of buggy software (e.g. by Novell) out there that trashes 
them.

Duncan Murdoch
dmurdoch@mast.queensu.ca

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From: dmurdoch@mast.queensu.ca (Duncan Murdoch)
Subject: Hardware interrupt mappings?
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Organization: Queen's University
Date: Wed, 30 Dec 1992 23:14:54 GMT