Date   : Mon, 09 Sep 2002 01:03:58 +0000
From   : "C Davies" <davies_@...>
Subject: Re: Regaining disc drive memory work space

If I remember correctly, you should use it to enable the machine to properly 
set the TOP and LOMEM values.


>From: pete@... (Pete Turnbull)
>To: "BBC Micro Mailing List" <bbc-micro@...>
>Subject: Re: [BBC-Micro] Regaining disc drive memory work space
>Date: Sun, 8 Sep 2002 23:16:47 GMT
>
>On Sep 7, 20:43, Richard Gellman wrote:
> > >> >   When using a disc drive on a BBC micro, Page is moved from &E00 
>to
> > >> > &1900 to create memory work space for the disc drive. Is possible
>  to
> > >> > regain the disc drive work space once the program has loaded. I.e
> > >> > resetting page back to &E00. Can anybody give an example of various
> > >> > techniques on how to achieve this.
> > >
> > >> You write your program thus:
> > >>
> > >> 10 IF PAGE<>&E00 GOTO 9000
> > >> ...
> > >> your program
> > >> ...
> > >> 9000 FOR I%=0 TO TOP-PAGE STEP
> > >> 4:!(I%+&E00)=!(i%+PAGE):NEXT:PAGE=&E00:OLD:RUN
> > >
> > >[snip]
> > >
> > >> OLD is needed to ensure BASIC is aware of the new program in memory.
> > >
> > >Except of course OLD can only be used at the command prompt,not 
>included
>in
> > >a program line,
> > >Sprow.
> >
> > Ah..
> >
> > Perhaps OLD is not needed then. But I've seen programs relocate in this
> > manner :)
>
>I thought you did need it.  I recall programming commands into a function
>key and then poking the key value into the buffer, for that reason.
>  However, I just tried it with a little 2-liner, and it worked.
>
>--
>Pete                                               Peter Turnbull
>                                           Network Manager
>                                           University of York




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