batari, on Sun Sep 19, 2010 1:29 AM, said:
The first thing I did was do a JAM opcode and it seems to do nothing but jump to FFFE/FFFF and stay there.
I also tried the opcodes considered unstable (ANE, LXA) and found LXA stable, and ANE to operate differently than documented on a C-64. This suggests that even though this claims to be a full simulation, perhaps it's not considering something (such as wire delay for race conditions that could go either way in real hardware, or effects of a floating bus.)
I plan to try some of the other weird opcodes and see what happens - also I may try to see what areas go active during these opcodes and compare with some of the neighboring valid opcodes as undocumented opcodes are usually a case of several valid opcodes being decoded and executed at the same time.
I haven't tried typing in a program to see how it works, and I wish there were a way to load a .bin into the RAM area, or at least type a short program into a text box using assembler opcodes. On the other hand, it's probably more useful to just type in a few instructions so you can watch what happens as they execute.
It will be interesting to see the TIA simulator in action, but I wonder how they'll implement it as far as the display is concerned? The main page says the TIA simulator is finished, but there's no page for it yet, so maybe they're still trying to work that out. For example, will there be a TV screen so we can watch the output being drawn, or will it just be the chip in action? And will a 6507(?) be shown alongside the TIA so we can see them interacting? Then there's the 6532 RIOT simulator that they're working on as well. It would be very cool if all three chips could be seen interacting, and possibly have console switches and input devices as well.
It would be ideal if the simulators worked in *all* browsers, because a lot of people do use IE, and they might get frustrated if they tried downloading and installing another browser, only to discover that the page *still* wouldn't load correctly. But I guess anyone who would be interested in the simulations in the first place would have to be a geek anyway, and would presumably have the smarts needed to figure out what the problem is and resolve it. Unfortunately for me, I'm not *that* big of a geek, and my smarts leave a lot to be desired, so it's a wonder I was able to figure out how to resolve the issue myself!