Re: Hardware emulation of 6509 using 6502?

From: Mia Magnusson <mia_at_plea.se>
Date: Wed, 7 Mar 2018 17:20:27 +0100
Message-ID: <20180307172027.000020e9@plea.se>
Den Tue, 06 Mar 2018 22:43:54 +0100 skrev Michał Pleban
<lists@michau.name>:
> Hello!
> 
> Mia Magnusson wrote:
> 
> > Well, the limit is that you can only access 1k in bank F, but there
> > seems to be no special limit on the usage of that 1k. Usually it's
> > probably best to use it for screen ram but in theory you could store
> > sprite data there instead, or whatever you want to have there.
> 
> I am not sure you can access the 1k of RAM because it lies at $0000,
> whereas the screen/char starts at $C000, and the VIC can only address
> 16k at a time.

I'm not talking about the 1k (or actually 2k according to the documents
I've read) starting at $0 in bank 15, but the 1k starting at $C000.

I see no reason for a technical limitation for using that 1k $C000 for
anything VIC-II can use memory for, although in most cases it seems
like a bad idea to use it for anything else than screen ram. (In theory
a cartridge game could use it for sprite data and change sprite data on
demand (animations e.t.c.) and run most of it's stuff completely in
bank 15.

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Received on 2018-03-07 18:03:46

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