Date: Tue, 30 Sep 1997 14:55:00 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Olivier Gremillet <gremille AT zeus DOT nt DOT op DOT dlr DOT de>
cc: djgpp AT delorie DOT com, gremille AT zeus DOT nt DOT op DOT de
Subject: Re: dos/windows problem in c
In-Reply-To: <3430A95E.49B9@zeus.nt.op.dlr.de>
Message-ID: <Pine.SUN.3.91.970930145136.6404A-100000@is>
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On Tue, 30 Sep 1997, Olivier Gremillet wrote:

> i cant not succed in compiling the following programm which wanted to
>  access to an adress for reading a card value
>  
>  unsigned long far* ch0data;
>  ch0data = (unsigned long far*) 0x4D000000
>  
>  ch0data[0320]=0L;
>  ---->  crash the protection mode of windows 3.11

This will never work.  You need to use special methods to access 
memory-mapped hardware in protected mode.  The issue is too complicated 
to explain here.  Please download the DJGPP FAQ list (v2/faq210b.zip from 
the same place you get DJGPP) and read sections 18.4 - 18.7 there.  They 
discuss this and related matters at length.