Re: [stella] 3F question

Subject: Re: [stella] 3F question
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Sun, 10 Jul 2005 15:33:49 -0400
> I've added code to 3F that makes it do both... but I just wanted to
> ask the experts and make sure I'm doing the right thing: A write to any
> of the standard TIA addresses on real 3F hardware will affect both the
> TIA and the bankswitching. Is this correct, and are there any special
> cases I should know about?

Yes, this is how the standard implementation of 3F bankswitching
works. There are no special cases regarding the TIA, but if you
want to go for 100% acuracy, you should also note that the bank
will only be changed, if the next address accessed after the
write to $003F is in the ROM area. So a STA $3F will work when
executed from ROM but not from RIOT RAM, because the next
address on the bus will be the opcode fetch for the instruction
after the STA $3F.

Ciao, Eckhard Stolberg

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