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From: "Charles Sandmann" <cwsdpmi AT earthlink DOT net>
Newsgroups: comp.os.msdos.djgpp
References: <850b568b-640c-435e-b6ca-deb8953ef1d5 AT y10g2000prf DOT googlegroups DOT com>
Subject: Re: How to access 0xFF800000 data ?
Date: Wed, 2 Sep 2009 23:47:53 -0500
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

> I try to use DJGPP to write an utility to flash BIOS.
> In the DJGPP, how to read/write 0xFF800000 data ?

In addition to using either far or near pointers, you also need to
map the address space with DPMI (function 0x800),
__dpmi_physical_address_mapping(__dpmi_meminfo *_info);

You can probably also use the PMODE DPMI provider if
you are running in RAW or XMS mode, since it does not
enable paging and you could access the memory directly.