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SubjectRe: Ram problems
On Wed, 17 Jul 1996, Alan Cox wrote:

> > As some one on this list already pointed out, we have to use
> > INT15 AX=E820 or AX=E801, if these are supported by the BIOS.
> > ( and all newer BIOSes do so )
>
> And some older BIOS return random results, so we have to look at
> all the evidence and guess

Yes, that's what I mean.
This also was proposed by Erich Stefan Boleyn <erich@uruk.org>, he has a
good description of INT15 AX=E820 at http://uruk.uruk.org/grub/mem64mb.html.

IMHO, its not a 'guess', unsupported INT15 function return with CARRY set
(this I verified on atleast 4 older machines). Also, INT15 AX=E820
returns a magic in EAX ('SMAP') and this makes the detection very sure.
We also could consider to take the BIOS-Date as additional check.

So we can detect when the newer INT15-functions are present and we can have
this order:

1. Try INT15 AX=E820, if ok take this.
2. Try INT15 AX=E801, if ok take this.
3. need to take INT15 AH=88

Hans
<lermen@fgan.de>




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