Date: Tue, 5 Jan 1999 03:49:36 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: mike@smith.net.au (Mike Smith) Cc: imp@village.org, hackers@FreeBSD.ORG Subject: Re: Information needed on SMI Message-ID: <199901050349.UAA03933@usr05.primenet.com> In-Reply-To: <199812211740.JAA02386@dingo.cdrom.com> from "Mike Smith" at Dec 21, 98 09:40:24 am
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> > Greetings,
> > I'm looking for information on the SMI bios stuff. I don't
> > mean Intel's SMBios, but the SMI in "Power management: APM, SMI" that
> > comes up when I boot my machine. My web searches have turned up the
> > Intel spec a lot, but nothing on SMI itself (except that this or that
> > computer support it).
>
> SMI is "system management interrupt", it causes the processor to enter
> SMM ("system management mode"). You'll find documentation on it in the
> Intel processor manuals, IIRC from the '486 onwards.
More specifically, given the context of the question, I'm going to
assume you have a Cyrix processor, like the Media/GX.
Most Cyrus processors assume the SMI handler is in the BIOS (which
has specific knowledge of the hardware).
This means that the BIOS gets called as a result of an SMI in response
to an APM event.
Depending on which computer you have, the BIOS may make assumptions
about how the hardware has been configured, or may expect to be
called in VM86() mode by an OS that intercepts the SMI interrupt
in protected mode and forwards it to the original BIOS vector.
Julian has *some* information on interfacing to the SMI, but I'm
not sure how much he can share.
Terry Lambert
terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.
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