From: Ian Miller <itmiller AT dra DOT hmg DOT gb DOT removeme>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Accessing PCI memory
Date: 14 Jul 1997 15:53:18 +0100
Organization: Defence Research Agency
Message-ID: <87en91lm75.fsf@hasn.dra.hmg.gb>
References: <33CA3306 DOT 2F2E AT signal DOT dra DOT hmg DOT gb>
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
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Gordon Brown <brown AT signal DOT dra DOT hmg DOT gb> writes:

> 
> If I have a PCI board located in the PC memory space at 0x3d000000 how
> do I access this memory using DJGPP.
> 
> I am new-ish to DJGPP & PC programming.
> 
> Any help is appreciated,
> 
> G. Brown
> brown AT signal DOT dra DOT hmg DOT gb

Actually, I don't know the answer; but I think I can point you in the
right direction. You won't be able to access global 0x3d000000 directly
because DJGPP programs switch the CPU into protected mode and therefore
see only their own private memory space. However, the graphics
programmers access the video card directly so this sort of thing is
certainly possible. There are a number of approaches - "far pointers"
spring to mind - and they are described in the DJGPP FAQ and many other
places on the Web. If you don't have a copy of the FAQ, I suggest you
start looking at DJ's DJGPP home page,

http://www.delorie.com/djgpp/

Don't omit the trailing slash or DJ's http server get's cross!

HTH
-- 
Ian Miller (BaeSEMA), SSSR104,
Defence Evaluation and Research Agency,
Winfrith Technology Centre, Dorchester,  Tel: +44 1305 212544
DORSET, DT2 8XJ, UK                      Fax: +44 1305 212116