Re: Hardware emulation of 6509 using 6502?

From: smf <smf_at_null.net>
Date: Thu, 15 Mar 2018 09:26:26 +0000
Message-ID: <401afd68-ec45-e5d0-f845-007b1bed5cc9@null.net>
On 14/03/2018 22:57, silverdr@wfmh.org.pl wrote:
> IMHO there is quite a difference between an emulator and the ultimate.

There is a difference between Vice and an ultimate (and for completeness 
chameleon), however they are all emulating a c64.

You avoid the latency imposed by serially emulating the logic, feeding 
data through usb peripherals, video card etc. I have no problem with the 
latency in vice & you also will get latency issues with some TV's 
anyway. The precense or absense of latency is not how you determine 
whether something is emulating something or not.

What Vice and Ultimate have in common is that they all require people to 
sit down and model the behaviour of the analogue and digital circuits in 
the 64, where some of the digital circuits suffer from analogue effects. 
How you structure that code is different between the two, but the 
ability to get the behaviour wrong is the same.

It's also much easier to hook up real sid chips/joysticks/etc to an 
ultimate than it is to Vice. Timing would be a major pain in Vice, but 
theoretically you could write an emulator that runs on a CPU without an 
OS which was able to adhere to the same timing as a real C64. If it had 
Unified memory and a reasonable shading language then you could emulate 
the VIC in real time and have no latency there either. It would require 
a fixed specification platform and a lot of time, it's easier to use an 
FPGA.

I bought a reloaded mk2 and I will probably buy a ultimate. I may regret 
going for the ultimate instead of a reloaded mk3, because the chameleon 
software has had more time spent on it than the ultimate software. 
However I like that the ultimate software is open source and the 
hardware is much cheaper.
Received on 2018-03-15 11:00:02

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