From:	Zach Heilig <heilig AT cs DOT und DOT nodak DOT edu>
Subject:	Re: A question about writing interrupt handler in gcc
To:	alh AT engr DOT engr DOT uark DOT edu (ALAN L HIGHTOWER)
Date:	Fri, 11 Nov 1994 20:44:30 -0600 (CST)
Cc:	djgpp AT sun DOT soe DOT clarkson DOT edu

ALAN L HIGHTOWER says:
>      How else will I change the vector table?  Using irq7 and not 
> chaining the previous handler locks the system up cold.

I don't recall there being anything important off IRQ7, unless your
sound card driver needs to be called for every interrupt.  Did you
forget to tell the pic that you were done servicing the interrupt?
all interrupts are blocked until you tell it that it's ok to service
more.  In general, at the end of your handler, you must send a 0x20 to
port 0x20 for any IRQ and a 0x20 to (I'm not sure where) for IRQs
8-15.

-- 
	Zach Heilig	(heilig AT aero DOT und DOT nodak DOT edu)

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