X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f
From: "Gerrit van Niekerk" <gerritvn AT gpvno DOT co DOT za>
Organization: GPvNO
To: tim DOT nicholson AT skyforcekent DOT com
Date: Fri, 23 Mar 2007 21:32:26 +0200
MIME-Version: 1.0
Subject: Re: protecting program memory
CC: djgpp AT delorie DOT com
Message-ID: <4604476A.28947.324D069D@gerritvn.gpvno.co.za>
In-reply-to: <1174648609.965097.60210@b75g2000hsg.googlegroups.com>
References: <1174648609 DOT 965097 DOT 60210 AT b75g2000hsg DOT googlegroups DOT com>
X-mailer: Pegasus Mail for Windows (4.41)
Content-type: text/plain; charset=US-ASCII
Content-transfer-encoding: 7BIT
Content-description: Mail message body
Reply-To: djgpp AT delorie DOT com
Errors-To: nobody AT delorie DOT com
X-Mailing-List: djgpp AT delorie DOT com
X-Unsubscribes-To: listserv AT delorie DOT com
Precedence: bulk

On 23 Mar 2007 at 4:16, tim DOT nicholson AT skyforcekent DOT co wrote:

> Is there an easy way to protect the memory used to store the program
> op codes from a rogue memory write from within the application? I have
> a large (100,000+ line) DJGPP application which sometimes crashes with
> SIGILL - It would seem the program is cannibalizing itself! In order
> to find how this is happening, I would like to protect the entire
> block of memory that contains the application code so that an
> exception occurs at the point the corruption occurs rather than the
> point that the corrupted code is executed.
 
I certainly thought code would be protected, but it is not - I have just tested it. 
What is the reason for that?