Re: Hardware emulation of 6509 using 6502?

From: smf <smf_at_null.net>
Date: Wed, 15 Nov 2017 15:16:24 +0000
Message-ID: <6c74bff3-68cf-2b61-84d0-f9333b615451@null.net>
On 15/11/2017 14:06, Gerrit Heitsch wrote:
>
>> Conventiently that covers the c64/plus4/c128, so as long as the 
>> undocumented opcodes are stable across all three then they are safe 
>> to use no matter what process the chip was made with.
>
> Did someone ever test that?
>
I don't know how well it's been tested, but between C64 (nmos) & C128 
(hmos-ii) and the plus 4 (hmos-i & hmos-ii). I would have thought there 
are a reasonable number that are in use, some of the opcodes aren't very 
useful.

Besides, the 65c02 isn't only incompatible because of undocumented 
opcodes. There were a few other changes too.



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Received on 2017-11-15 16:00:02

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