From:	"Michael Schuster" <Schuster AT eev DOT e-technik DOT uni-erlangen DOT de>
Organization:	LS f. Elektr. Energieversorgung
To:	Josh Turpen <snarfy AT goodnet DOT com>, djgpp AT delorie DOT com
Date:	Thu, 19 Dec 1996 08:20:37 MEZ
Subject:	hardware interrupts again
Message-Id:	<E99EF55425@merlin2.e-technik.uni-erlangen.de>

Hi out there, hi Josh!

Thanks again.

> Better? :)  There is one thing though that I forgot to mention:
> You need to acknowledge the interrupt to the interrupt controller by
> doing an "movb $0x20,al;  out $0x20,%al" .  The interrupt controller
> won't generate an other interrupt if you don't do that.  

Remember: I told *now * my interrupts work fine, so I did of course 
confirm the interrupts -I made this in C with a outportb (0x20,0x20).
Also if you program a Slave IR (IR8..IR15) you have to outportb 
(0xA0,0x20) additionally.

Still my question to all of you:
> > But I still donot understand why the Interrupt works, the programm 
> > is running, but when releasing the interrupt or shutting down the 
> > program,  why the program  crashes.
> > Also non array, global variables, are still in use in my 
> > interrupthandler, and they don't harm anything (till now). Is this ok, then?


> Try this program, as an example: (it uses go32, but thats ok, its easy)
If you want to do a hardware interrupt, you also have to program the 
controller. 
I did this, and it works perfectly. The only thing, which won't work with my 
hardwareinterrupts, is a array defined as 

array_type data [const x][const y]

but when

array_type **data 

everthing works.

Michi 
**********************************************
Michael Schuster
E-mail: Schuster AT eev DOT e-technik DOT uni-erlangen DOT de

Universitaet Erlangen/Nuernberg
Lehrstuhl fuer Elektrische Energieversorgung
Cauerstrasse 4
91058 Erlangen

http://www.eev.e-technik.uni-erlangen.de/
**********************************************

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