From:	Prashant TR <prashant_tr AT yahoo DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: far pointers
Date:	09 Jun 2000 13:41:39 +0530
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Gaurang Kanvinde <n8007034 AT ccs DOT iitb DOT ernet DOT in> writes:

> How do I access memory registers in C? DJGPP gcc does not recognise  the
> far pointers that can be used otherwise. Instead,   _farpeek and
> _farpoke functions are used.

The reason for this is explained in the FAQ and it requires some
knowledge of Protected Mode.

> Can someone tell me how to use these functions?. What are the SELECTOR
> and OFFSET arguments in these functions?

_dos_ds is the selector value (Add #include <go32.h> to your source
file) generally. The offset is the linear address. For example, if you
wanted to access the long integer value at F000:FFFF, you'd write
_farpeekl(_dos_ds, 0xffff0); // That was 0F000h * 0x10 + 0xFFFF.

Btw, I'll add some document on protected mode on my site something
today evening. You might want to check that out.

When available, it will be at http://www.midpec.com/djgpp/protmode/

Hope this helps!

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