Path: utzoo!lsuc!ncrcan!brambo!morgan
From: morgan@brambo.UUCP (Morgan W. Jones)
Newsgroups: comp.sys.amiga
Subject: Re: Need info on exceptions
Message-ID: <415@brambo.UUCP>
Date: 26 Aug 88 02:46:33 GMT
References: <3793@louie.udel.EDU>
Reply-To: morgan@brambo.UUCP (Morgan W. Jones)
Organization: Bramalea Software Inc., Bramalea, Ont.
Lines: 25

In article <3793@louie.udel.EDU> iphwk%MTSUNIX1.BITNET@cunyvm.cuny.edu (Bill Kinnersley) writes:
>[In "Re: Need info on exceptions", "Morgan W. Jones" said:]
>> course, you'd have to make sure that a swi can do things like delete
>> messages, send messages, open files, etc.
>Unfortunately it can't.  "To avoid serious problems, the interrupt
>routine must not use any of the memory allocation or deallocation
>functions"--RKM.  That's apparently because critical system code
>is surrounded by Forbid(), but not Disable().

I'm not so sure.  True, if you are dealing with "real", harware
generated interrupts you run into this problem.  Software interrupts,
however, are generated by the operating system.  Thus, it seems that
it would be impossible to destroy kernel data from inside a software
interrupt - they should all be valid.  Software interrupts are
actually recommended in the RKM for use when you want to do a lot of
processing inside an interrupt so that the system doesn't slow down -
this implies that the system multi-tasks during software interrupts
and so the software interrupt should appear as a task to the O/S.

Any Gurus want to comment on this?

-- 
Morgan Jones                                 morgan@hcr.UUCP
Human Computing Resources, Toronto, Canada
"BMATH - 8 months and counting ..."