Messages in this thread |  | | Date | Thu, 18 Jul 1996 18:38:45 +0200 (MET DST) | From | Hans Lermen <> | Subject | Re: Ram problems |
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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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