Date: Thu, 2 Dec 1999 09:51:08 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To: Prashant TR <prashant_news AT yahoo DOT com>
cc: Gareth Williams <ghw2002tii AT hotmail DOT com>, djgpp AT delorie DOT com
Subject: Re: Setting a variable's selector?
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On Thu, 2 Dec 1999, Prashant TR wrote:

> >In order to get information from the PnP BIOS I need the data structure to
> >reside in the same selector/segment as the BIOS entry point.
> 
> What exactly do you mean by this? The PnP BIOS obviously
> resides in the ROM which is read-only and so you *cannot*
> have your data sturctures in the same segment as the entry
> point.

This is not necessarily true: in protected mode, at least in
principle, you can set up a selector to span any range of addresses in
the 4GB address space.  The code in ROM does have an address, so it
can be inluded.

> Don't think so. But you're mixing up segments and selectors. The
> name "selector" is when you're refering to prot. mode and "segment"
> when you're using real mode.

Not entirely true: protected mode doesn't disable memory segmentation.
You do have segments in a DJGPP program, and a selector is an index
into the table of segment descriptors.  So a selector does specify a
segment, albeit indirectly.