Comments: Authenticated sender is <alaric+abwillms AT sdps DOT demon DOT co DOT uk>
From: "Alaric B. Williams" <alaric AT abwillms DOT demon DOT co DOT uk>
To: yeep <yeep AT xs4all DOT nl>, opendos-developer AT mail DOT tacoma DOT net
Date: Fri, 21 Mar 1997 22:13:17 +0000
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Subject: Re: 32bit BIOS
Reply-to: alaric AT abwillms DOT demon DOT co DOT uk
In-reply-to: <199703211724.SAA13023@magigimmix.xs4all.nl>
Message-ID: <858982431.0526030.0@abwillms.demon.co.uk>

On 21 Mar 97 at 18:20, yeep wrote:

> From:          "yeep" <yeep AT xs4all DOT nl>
> To:            "OpenDOS" <opendos AT mail DOT tacoma DOT net>
> Subject:       32bit BIOS
> Date:          Fri, 21 Mar 1997 18:20:18 +0100

(Another ported thread)

> Some guy posted something about why the bios creators (Award, AMI) don't
> create 32bit bioses.

> Well It just occured to me, that that's because the CPU's natural state is
> 16bit.
> So first the CPU should boot up (or start or whatever) in 32bit mode, then
> the bios can be 32bit and we shall all be happy.

Well, not quite. If the CPU is in protected mode with a 32 bit code 
segment, standard DOS software won't run, DOS won't run, and nothing will
be able to boot without a custom bootloader that uses the new standard.

It's easier to have the system boot in real mode, as per standard, but provide
a protected mode interface in the BIOS, like the VESA folks did.

> Ofcourse....unless the bios sets the CPU in 32bit mode, before doing
> anything else....hmmmmm...

Yes, exactly. A 32 bit protected mode OS starts in 16 bit real mode, doesn't it?

ABW
--
Alaric B. Williams (alaric AT abwillms DOT demon DOT co DOT uk)

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