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From: apratt@atari.UUCP (Allan Pratt)
Newsgroups: comp.sys.atari.st
Subject: Re: How can I access lower ram?
Message-ID: <793@atari.UUCP>
Date: Wed, 22-Jul-87 13:44:35 EDT
Article-I.D.: atari.793
Posted: Wed Jul 22 13:44:35 1987
Date-Received: Sat, 25-Jul-87 04:04:50 EDT
References: <580@ritcv.UUCP>
Organization: Atari Corp., Sunnyvale CA
Lines: 33

in article <580@ritcv.UUCP>, mdr7527@ritcv.UUCP (Mark Rogalski) says:
> 
> Can anyone tell me how I can use lower RAM area using Malloc or something
> similar. Apparently the lower 120K can not be gotten to easily because 
> TOS uses that address range even if it is in ROM. Is this correct?
> 
>    Thanks for any help.
> 				Mark

Your question is hard to answer because I can't figure out what you mean.
Malloc allocates a (previously free) chunk of RAM for your use, and you
are expected to Mfree it later.  When your process terminates, that memory
is freed for you.

When TOS is in ROM it still has to use *some* RAM, right? For its
variables and things.  In my system, with a hard-disk driver, FLDR100,
and a 128K RAMdisk, the first program loads at about 200K. 

The point is you don't have to care where your program loads, because
TOS will relocate it for you.  Also, when you start up, you get the
largest free chunk of memory, so I don't know why you need more.

Finally, there are some locations in low memory (at and above $400)
which are "system variables" -- variables you can change to alter
system behavior.  You have to be Supervisor to change these.

If this doesn't answer your question, please rephrase it and I'll
try again.

/----------------------------------------------\
| Opinions expressed above do not necessarily  |  -- Allan Pratt, Atari Corp.
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