From:	Andrea Martino <amartino AT iiic DOT ethz DOT ch>
Newsgroups:	comp.os.msdos.djgpp
Subject:	DJGPP & PMODE FEATURES
Date:	Fri, 16 May 1997 09:32:15 +0200
Organization:	Swiss Federal Institute of Technology (ETHZ)
Message-ID:	<337C0D7F.4FAA@iiic.ethz.ch>
NNTP-Posting-Host:	slab136.ethz.ch
Mime-Version:	1.0
Lines:	18
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Hy, I`m new to DJGP world...   :)

I want to acces video memory (0xA0000), but, when I try to do it, the
compiler returns a SIGSEG. I have to tell the compiler that I CAN
"touch" and "write" the video memory, but I don`t know how to do this.
What is the best way to do this?

Some people (<- thanx) told me that I MUST use some DPMI features like
selector & descriptors (GDT, LDT).

*** What are exactly selectors and descriptors (GDT & LDT)???
*** How knows the compiler that I CAN "write" some memory (like the
memory that I alloc), but I CAN`T "write" other memory (like video one)?

Thanx

P.S. It`s possible to carbon copy the answer to my e-mail adress
(because I cannot read the news everyday).

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