Mapping Video BIOS?

[Greg 'groggy' Lehey]

On Sunday, 27 July 2003 at 22:03:57 -0600, M. Warner Losh wrote:
> In message: <20030728040157.GP45069 at wantadilla.lemis.com>
>             "Greg 'groggy' Lehey" <grog at FreeBSD.org> writes:
>> Sure.  The data at offset 0xc0000 are:
>>
>> C000:0000  55 AA 78 E9 44 06 00 00-00 00 00 00 00 00 00 00   U.x.D...........
>>
>> The 0xaa55 is the BIOS signature ("Here be a BIOS"), and the 0x78 is
>> the length byte (120 sectors, or 60 kB).  That's how orm0 knows the
>> end address.
>>
>>> I don't think that it suggests that things are 'unmapped'...
>>
>> If the area between 0xcc000 and 0xcffff had been mapped, orm0 would
>> have found this too:
>>
>> C000:F000  55 AA 08 E8 6D 0B CB 11-FE 02 00 00 00 00 00 00   U...m...........
>
> 08 -> 4k

Correct.  It should have shown a BIOS from 0xcf000 to 0xcffff

> It could also be that there's a bug in orm that's missing it...

Sure, but given the other indications, that's not so likely.

Greg
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