Date   : Sun, 08 Sep 2002 23:16:47 GMT
From   : pete@... (Pete Turnbull)
Subject: Re: Regaining disc drive memory work space

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