flat assembler
Message board for the users of flat assembler.

flat assembler > OS Construction > If EMM386 put you in v86 mode, how did Windows get to pmode?

Author
Thread Post new topic Reply to topic
StringCheesian



Joined: 20 Feb 2004
Posts: 20
Is it possible to switch to pmode even with EMM386 running (ie while in virtual 86 mode)? No it's not, right? Then how did Windows do it...?
Post 11 Mar 2004, 06:29
View user's profile Send private message Reply with quote
Gomer73



Joined: 29 Nov 2003
Posts: 151
The thing is, EMM386 is microsoft code, so obviously they can call functions to do whatever they want.

There is some function discussed somewhere that discusses which int will allow you to do this. I forget where I saw this though. I can't think why there would be a need for it though.
Post 11 Mar 2004, 06:37
View user's profile Send private message Reply with quote
neonz



Joined: 02 Aug 2003
Posts: 62
Location: Latvia
Post 17 Mar 2004, 04:36
View user's profile Send private message Visit poster's website Reply with quote
StringCheesian



Joined: 20 Feb 2004
Posts: 20
Thank you, neonz!

So that works under EMM386, but not in a DOS Prompt under Win 3.1 or 9x, right?
Post 17 Mar 2004, 04:47
View user's profile Send private message Reply with quote
neonz



Joined: 02 Aug 2003
Posts: 62
Location: Latvia
StringCheesian wrote:
Thank you, neonz!

So that works under EMM386, but not in a DOS Prompt under Win 3.1 or 9x, right?


dunno, you can also try VCPI - http://www.nondot.org/sabre/os/files/ProtectedMode/VCPI.txt
Post 17 Mar 2004, 07:31
View user's profile Send private message Visit poster's website Reply with quote
f0dder



Joined: 19 Feb 2004
Posts: 3170
Location: Denmark
A DOS box should only allow DPMI access to pmode, anything else would be too dangerous in the context of a protected mode operating system.
Post 18 Mar 2004, 13:46
View user's profile Send private message Visit poster's website Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  


< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Copyright © 1999-2019, Tomasz Grysztar.

Powered by rwasa.