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From: svincent AT zippy DOT sonoma DOT edu (Sam Vincent)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: interrupt stops being invoked
Date: 9 Sep 1995 21:39:04 GMT
Organization: Information Resources and Technology
Lines: 28
References: <DEGo90 DOT Fpz AT jade DOT mv DOT net>
Nntp-Posting-Host: zippy.sonoma.edu
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway: from newsgroup comp.os.msdos.djgpp

Brendan Simon (brendan AT rdt DOT monash DOT edu DOT au) wrote:
: >From: Sam Vincent <svincent AT zippy DOT sonoma DOT edu>
: >You must use djgpp version 2.0 and lock the memory touched by the interrupt
: >routine in order to grab a hardware interrupt.. otherwise the paging
: >mechanism (due to virtual memory) could end up triggering a page fault
: >in the middle of a hardware interrupt..  (not good.. a machine lockup)
: >
: >-Sam

: Yes I should do this (I don't know how yet.  I am using V2)

: I have a 16Mb machine (486DX100) and there seems to be no swapping to disk.
: I should elaborate that the program sill runs but the interrupt routine 
: doesn't seem to be invoked any more.  ie the getkey statment I have in a loop
: still gets executed and prints my nice graphics (grx2.0) appropriately.

: So maybe the PIC gets confused.  I'm not sure.  
: I'll try the locking to see if it helps.

: Thanks, Brendan.
: brendan AT rdt DOT monash DOT edu DOT au

Ah.. sounds like you were forgetting do do an outport(0x20, 0x20) to tell 
the hardware that you're done processing the interrupt and it can
allow new interrupts...

-Sam