Path: utzoo!attcan!uunet!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Shared Interrupts
Keywords: "not supported" interrupts
Message-ID: <14490@cbmvax.commodore.com>
Date: 17 Sep 90 18:34:24 GMT
References: <28208@swrinde.nde.swri.edu> <14444@cbmvax.commodore.com> <1990Sep15.011910.704@ecst.csuchico.edu>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 28

In article <1990Sep15.011910.704@ecst.csuchico.edu> mrush@cscihp.UUCP writes:
>In article <14444@cbmvax.commodore.com> daveh@cbmvax.commodore.com (Dave Haynie) writes:

>>The interrupts are level-sensitive (except for level 7, NMI, which isn't 
>>supported in the A2000).  

>	What does that mean that level 7, NMI, interrupts aren't supported in
>the A2000?  Is that to say that it is impossible for anything to assert a level
>7 interrupt, or that if anything does it will be ignored?

It means that a level 7 interrupt can break a Disable().  The way the extra
expansion bus interrupts (levels 1,4,5, and 7) were defined on the A2000, they
didn't pass through any sort of interrupt controller like the level 2 and 6
interrupts do.  So there's no disabling mechanism, and therefore no support for
them under AmigaOS.  The A3000 has an interrupt controller that properly 
supports these extra interrupts, at least if you're using the 2.0 definitions
of Disable and Enable.

>There's a Margarita waiting for ya any time you find yourself in Chico!

A way's to go just for a drink, but if I'm ever in the neighborhood...

>	-- Matt

-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
      Get that coffee outta my face, put a Margarita in its place!