Date   : Wed, 12 Oct 2005 17:41:37 +0100 (BST)
From   : Matt Callow <mattcallow@...>
Subject: Re: BBC Rom File Structure

--- Jeff Gaines <jeff@...> wrote:

> Hello Group,
> 
>   I am putting together a small app to manage the ROMs in
> BeebEm,
>   ROMMgr doesn't seem to be able to manage it, since it looks
> like the
>   structure of the .cfg files has changed, and cfg seems to
> have the
>   path to BeebEn hard coded so I can't use it.
> 
>   Most of it seems straightforward but I would like to read in
>   information from the ROM image like name, copyright etc.
> From
>   examining a few ROMs in a hex editor they don't have
> 'standard'
>   layouts, I guess they can't because the length of the name
> will
>   differ and also the length of the name of the copyright
> holder.
> 
>   I have tried a Google and a poke round the (large number) of
> Beeb
>   sites without success.
> 
>   Does anybody know how the structure of these ROM files is
> set up, or
>   where might be a  good place to find out?
> 
>   Many thanks.
> 
> -- 
> Regards
> Jeff Gaines
> Damerham Hampshire UK
> 
> 
It's in the advanced user guide, available from
http://www.bbcdocs.com/

Here is what it says on page 317

A paged ROM must be recognised by the operating system. To be
recognised the first few bytes must conform to:

00-02  JMP language entry
03-05  JMP service entry
06     ROM type
07     Copyright offset pointer (=nn)
08     Binary version number
09..   Title string, printed on selection as a language.
vv..   Optional version string, preceded by &00.
nn-nn+3        &00, &28 '(', &43 'C', &29 ')'
 
       nn+4..  Copyright message
xx     Copyright message terminator (&00)
xx+1-xx+5      If applicable, second processor relocation address.

Matt


       
       
               
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