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Any way to access BIOS in pmode?
Posted: Thu Feb 22, 2001 12:00 am
by Collin
Hello,
I have what may seem to be a rather unintelligent
question: is there _any_ way to access the BIOS in pmode?
Yes, I have read several FAQs and tutorials that say
there isn't a way, but I am still wondering if there
is some programming trick through which one might access
the BIOS while in pmode. Thanks.
Collin
RE:Any way to access BIOS in pmode?
Posted: Thu Feb 22, 2001 12:00 am
by Chase
>On 2001-02-22 16:14:12, Collin wrote:
>
>I have what may seem to be a rather unintelligent
>question: is there _any_ way to access the BIOS in
pmode?
Yes, by using a virtual mode task. You have to create
a virtual mode manager that handles exceptions when certain
instructions are executed (like a cli). You also need to
mess like I/O privlage levels, etc.
You probable should create a complete set of pmode
exception
handlers that print error msgs direct to video memory. Then
start on the vmode stuff.
RE:Any way to access BIOS in pmode?
Posted: Sat Feb 24, 2001 12:00 am
by Guest
I think the best way is to use r-mode portal. To switch to
rmode back , cause an interrupt , and go back to pmode, it's
slow, but..
RE:Any way to access BIOS in pmode?
Posted: Sat Feb 24, 2001 12:00 am
by Collin
>On 2001-02-24 17:45:03, Anonymous wrote:
>I think the best way is to use r-mode portal. To switch
to
>rmode back , cause an interrupt , and go back to pmode,
it's
>slow, but..
OK, I'll try that. It might be the easiest way.
Collin
RE:Any way to access BIOS in pmode?
Posted: Fri Mar 02, 2001 12:00 am
by tOwk
Depending on what you need from BIOS it should _PROBABLY_ be possible to read it direct from the memory (that's also where interrupts should be stored, in the BIOS chip). But you should take care on executing any of that because it's a 16bit code.
NOTE: I have not tried any of this, it's just an idea that _MAY_ (but not necessarily will) work. Also, it might be that BIOS is not mapped in memory anymore when you switch to pmode, so please correct me if I am wrong.
RE:Any way to access BIOS in pmode?
Posted: Sat May 19, 2001 11:00 pm
by Shane
If you know exactly what you need beforehand, you could access
it in real mode and save it to a memory location that's
available in protected mode.
>On 2001-02-22 16:14:12, Collin wrote:
>Hello,
>
>I have what may seem to be a rather unintelligent
>question: is there _any_ way to access the BIOS in pmode?
>Yes, I have read several FAQs and tutorials that say
>there isn't a way, but I am still wondering if there
>is some programming trick through which one might access
>the BIOS while in pmode. Thanks.
>
>Collin