Mapping Video BIOS?

[M. Warner Losh]

In message: <20030728044238.GW45069 at wantadilla.lemis.com>
            "Greg 'groggy' Lehey" <grog at FreeBSD.org> writes:
: On Sunday, 27 July 2003 at 22:32:42 -0600, M. Warner Losh wrote:
: > In message: <20030728043155.GV45069 at wantadilla.lemis.com>
: >             "Greg 'groggy' Lehey" <grog at FreeBSD.org> writes:
: >> On Sunday, 27 July 2003 at 22:17:32 -0600, M. Warner Losh wrote:
: >>> In message: <20030728041557.GU45069 at wantadilla.lemis.com>
: >>>             "Greg 'groggy' Lehey" <grog at freebsd.org> writes:
: >>>> On Sunday, 27 July 2003 at 22:11:29 -0600, M. Warner Losh wrote:
: >>>>> Where are you getting the data?  A windows tool?
: >>>>
: >>>> If you're talking about the BIOS contents I'm printing, yes, I'm using
: >>>> a Microsoft tool called DEBUG (which has been around since before
: >>>> Microsoft bought DOS :-).
: >>>
: >>> I don't suppose that you could use FreeBSD's /dev/mem + od?
: >>
: >> Yup, can do.
: >>
: >>> dd if=/dev/mem bs=64k skip=12 count=1 | hd | less
: >>
: >>   00000000  55 aa 78 e9 44 06 00 00  00 00 00 00 00 00 00 00  |U.x.D...........|
: >>   00000010  00 00 00 00 00 00 00 00  68 01 00 00 00 00 49 42  |........h.....IB|
: >>   ...
: >>   0000bff0  04 03 80 00 0c 00 00 00  20 00 10 0b 3e 00 02 40  |........ ...>..@|
: >>   0000c000  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
: >>   *
: >>   00010000
: >>
: >> That's pretty much what I expected.  Up to offset bff0, it's identical
: >> with the Microsoft dump.
: >
: > Shouldn't you be looking at 0x000c0000 instead of 0x0000c000?
: 
: Yes, I am.  Look at the calculations in the dd above: skip 12 blocks
: of 64 kB, or 0xc0000.  If you mean the output of Microsoft's DEBUG,
: that's in 8086 real mode, segment:offset.  The segment registers are
: logically shifted 4 bits to the left, so C000:0000 is 0xc0000.

No, didn't see the skip.  Looks like weird things are going on :-(

Warner