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Index > OS Construction > Real Mode Paging

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Mota



Joined: 29 Dec 2004
Posts: 22
Mota
Simple question:

Is it possible to enable paging within real mode, without ever enabling protected mode?

If so, how exactly would it work? Razz
Thanks in advance.
Post 06 May 2006, 21:44
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xorboy



Joined: 29 May 2006
Posts: 1
Location: sweden
xorboy
There is probably only way to do that:
Virtual real mode

Goto pmode, enable paging, set up the virtual realmode things, and then jump to it (through a special gate i think?) and you are done. The next question is why you would like to do that Razz You can at a maximum just access 1MByte RAM anyways Razz

Perhaps unreal mode is more interesting for what you had in mind. (goto pmode, set up a global descriptor table, set the segment registers accordingly, return back to realmode without ever changing the segregisters and suddenly you've got yourself a flat address-space in realmode, aka flat realmode, unreal mode. i think there is a piece of code that does this in the exaple's collection at fasm.)

You can find the specs on how to do that in intels 80386-manual. use google Razz
Post 29 May 2006, 10:27
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