Mail Archives: djgpp/2001/05/27/11:00:10
"Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il> wrote in message
news:3791-Sun27May2001163748+0300-eliz AT is DOT elta DOT co DOT il...
> > From: "Paul Gardiner" <paul AT laser-point DOT co DOT uk>
> > Newsgroups: comp.os.msdos.djgpp
> > Date: Sun, 27 May 2001 12:45:00 +0100
> > >
> > > Overlays are for programs whose code is too large to fit into the
> > > available amount of memory. DJGPP supports up to 2GB of memory
> > > (including virtual memory) on plain DOS, and about 128MB of memory on
> > > a typical Windows machine, so you shouldn't need any kludges such as
> > > overlays when you compile your programs with DJGPP.
> >
> > I wanted to provide a new implementation of an existing .ovl file.
>
> I don't think you can: you will need to reimplement the entire
> program, not just one of its overlays.
Sorry, I'm not explaining myself at all well. What I want to do is write a
replacement for glide2x.ovl. As far as I know, this is a sort of dll, but
for
DOS rather than Windows. So its not the usual reason for using overlays.
Its just a way to get dynamic linking with DOS. That's my understanding,
but I could well be wrong.
> > Have I misunderstood what DJGPP is about?
>
> I don't know; what _did_ you understand DJGPP was about?
:-)
> In a nutshell, DJGPP is a compiler and a suite of development tools.
That's what I thought really, but I guess what I don't understand is how it
relates to other development systems for DOS, with regard to compatibility.
I need binary compatibility with whatever was used to generate
glide2x.ovl. There must be some sort of spec covering the format of ovl
files,
unless it was just that all game developers of that era used the same tools.
> > Thanks for the quick reply, byt the way - especially on a Sunday. :-)
>
> You are welcome.
Ta.
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