Date   : Wed, 24 Jun 2009 18:20:09 +0100
From   : robert@... (Rob)
Subject: Co-Processor RAM Available to Languages

On 24/06/2009, David Harper <dl.harper@...> wrote:
> Ian Wolstenholme wrote:
>
>> Is there a way of making RAM in an internal co-processor available
>> to the current language whilst the co-processor is disabled?

> This is what I would like to have done when I first wrote CPFS, but I
> couldn't think of a sensible way of slotting the extra RAM into the Beeb's
> memory map.

I suppose you could possibly use the normal paging scheme using FDxx
for data, with paging register at FCFF/FCFE....  You'd have to detach
the RAM from the co-processor CPU, though, and attach it to the beebs
bus. I've used simple 8 bit TTL tri-state buffers to do this sort of
thing in the past (25 yrs ago!).

There was some discussion on this generally back in March..

Rob