Date: Mon, 27 May 1996 08:22:34 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: "Jeremy W. Deats" <jeremy AT neosoft DOT com>
Cc: djgpp AT delorie DOT com
Subject: Re: Simple mode 13h stuff... why doesn't this work?
In-Reply-To: <jeremy.27.00190156@neosoft.com>
Message-Id: <Pine.SUN.3.91.960527081838.9483E-100000@is>
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On Sun, 26 May 1996, Jeremy W. Deats wrote:

>  Can anyone tell me why this doesn't work?

The villain is the following line:
 
> unsigned char *video_buffer = (unsigned char *)0xe00a0000L;

and your belief that you can just get away with poking an arbitrary
address like this: 

>   for (i=0;i<64000;i++)
>    { video_buffer[i]=color; }

DJGPP is a protected-mode environment which won't allow you to write to 
any address you want, unless you ask nicely.

The DJGPP FAQ list (v2/faq200b.zip from the same place you get DJGPP) has 
full details, beginning at section 10.1.