Re: Big Real Mode above 4Gb

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Article #203

#203

From: Tim Robinson
Date: Sun, 08 Sep 2002 18:56

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MGMidget <twestern@earthlink.net> wrote:
| I wanted to have the Real Mode memory addresses act like they are
| remapped to the 4Gb to 8Gb region (sort of like V86 mode I suppose?).
| This would allow me to reuse/recyle some Big Real Mode code that
| needs to address above 4Gb.
|
| I was trying to either:
|     1) get an address remapping capability to work so that data
| access in the 0-4Gb region is really remapped to 4Gb-8Gb in Big Real
| Mode.
|
|     2) or,  find a way to extend the address to 36 bits in Big Real
| Mode - perhaps via Paging in Big Real Mode (?).

There *is* no 4GB to 8GB region on the x86, PAE or no. PAE would let you
access more than 4GB of *physical* memory, via paging, but the size of the
*virtual* address space is the same regardless. In any case, you can't use
paging (and hence PAE) outside of full protected mode.

If you want an address space bigger than 4GB, switch to using a 64-bit CPU.

--
Tim Robinson
http://www.themoebius.org.uk/

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From: "Tim Robinson" <tim_at_gaat.freeserve.co.uk@nowhere.com>
Newsgroups: comp.lang.asm.x86,intel.microprocessors.pentium_iii
Subject: Re: Big Real Mode above 4Gb
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