Date   : Mon, 20 Nov 2006 21:54:11 +0000
From   : pete@... (Pete Turnbull)
Subject: : BASIC variations

Thomas Harte wrote:
> Littlefield Aaron wrote:
> 
>> Please excuse my ignorance here, but purely out of interest, is it
>> possible to put a Master BASIC IV ROM into a humble Model B, or B+?
>> 
> As I understand it, this wouldn't be possible. From what I've read,
> the IV ROM fits a few extra commands in by replacing some other bits
> of code with shorter versions that rely on 65C02 specific opcodes. I
> couldn't tell you my source for that piece of information though, and
> I definitely don't claim it as first hand knowledge.

If you replace the 6502 in the Beeb with the right type of 65C02, it 
will work.  I've done that.  However, there are two families of 65C02 
with slight differences in the extended ocodes, and only one works. 
Sorry, I can't remember which ;-)

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York