Date: Sun, 27 Jul 2003 22:46:18 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: grog@FreeBSD.org Cc: freebsd-mobile@FreeBSD.org Subject: Re: Mapping Video BIOS? Message-ID: <20030727.224618.126221487.imp@bsdimp.com> In-Reply-To: <20030728044238.GW45069@wantadilla.lemis.com> References: <20030728043155.GV45069@wantadilla.lemis.com> <20030727.223242.40628033.imp@bsdimp.com> <20030728044238.GW45069@wantadilla.lemis.com>
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In message: <20030728044238.GW45069@wantadilla.lemis.com>
"Greg 'groggy' Lehey" <grog@FreeBSD.org> writes:
: On Sunday, 27 July 2003 at 22:32:42 -0600, M. Warner Losh wrote:
: > In message: <20030728043155.GV45069@wantadilla.lemis.com>
: > "Greg 'groggy' Lehey" <grog@FreeBSD.org> writes:
: >> On Sunday, 27 July 2003 at 22:17:32 -0600, M. Warner Losh wrote:
: >>> In message: <20030728041557.GU45069@wantadilla.lemis.com>
: >>> "Greg 'groggy' Lehey" <grog@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
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