Author here. The most recent change is that I started adding debugging UIs to the emulators, using the excellent Dear ImGui (https://github.com/ocornut/imgui).
The UI is updated once per 60Hz frame, so you only see a per-frame snapshot of the microchip pins which on its own isn't that useful yet except for a nice blinkenlight effect, but it will make a lot more sense once a step-debugging window is added. This will let you inspect the pins after each CPU instruction (still not as accurate as the emulation, which is running with machine-cycle granularity on Z80, and clock-cycle granularity on 6502 machines.
The emulators are written in C(99), with some platform-specific bits written in Objective-C and Javascript, and in C++ for the UI parts (since Dear ImGui is implemented in C++). Apart from the WebAssembly version, Win32, Linux, OSX and iOS is also supported, but you need to compile those yourself :)
Writing emulators is a lot of fun. Great stuff here :) Kudos!!!
A little off-topic: I end up doing a sub par job at writing some classic 8-bit emulators myself. At first it looks pretty straightforward, but becomes daunting as I progress, end up losing motivation for a couple of days before starting yet another project. How do you correctly learn this magic?
True, in the beginning it's tough because it takes so long until you can actually run small emulated programs and even then there's no real emulated computer yet, just a CPU. What kept me motivated was that I really wanted to play the games I wrote as teenager again and there were only very few existing emulators for this system, and none as easy to get running as just navigating to a webpage. There was also a bit of (unfounded) fear that those games would be lost since my own cassette tapes have rotted (unfounded because other people took care during the 90's to digitize the tapes and put them on the internet).
Once I had the first machine working (which required Z80 CPU, CTC and PIO emulations), it was fairly easy to build emulators for the other East German 8-bitters, and after that for the ZX Spectrum, and with each new machine it becomes easier and the chip emulations become better...
Another factor is that the emulators are only like a fallback project which I return to when I don't feel like doing something else (usually I reserve my Christmas vacation for this), and the emulators are also a nice testbed for my other projects (the sokol cross-platform headers, and generally doing WebAssembly stuff). These are small complete applications, yet built from very little code, so they're quite easy to maintain and experiment with.
If it's the right file format (.z80 snapshot file), you can drag'n'drop local files into the browser window while the correct ZX version is running (48K vs 128).
> I am wondering if there is any value of having old hardware around anymore.
It's definitely useful when you write emulators.. particularly if you're writing the only one in existence (and that's not so unusual, if you're targeting a relatively obscure mini, for example). I've written two emulators/simulators, I have hardware for one of them and that'll let me figure out the missing corner cases (not documented, or poorly documented), but I don't have hardware for the other one - and there are three or four undocumented areas. I wish I had the hardware.
This is hardware I used to work on in the eighties and early nineties. One day you kind of wake up to the fact that it's all gone, from everywhere.
It's another story if you just using (already existing) emulators. But for many people it's not really the same thing. It could be the speed, the mechanics, the hands-on.. heck, I lost the interest in pinball arcade machines when they replaced the mechanical score counter with LED counters. Can't really explain it, but the magic somehow evaporated.
It was released the same year the App Store launched. My wife was addicted to that game. The game and the author later disappeared. When my wife's phone was stolen in Rome, she couldn't re-download the game because it wasn't available on the App Store anymore.
Shame, too, because it was a really good game. I think it was the first app we ever paid for.
But it's likely 32 bit only and won't work anyway on anything newer than iOS 10.
Actually, there's a decent chance it won't even work in iOS 10 or would have major glitches, because legacy compatibility in iOS just isn't great in general.
And it's literally impossible to downgrade to an older OS version after Apple has closed the signing window.
This is the same that occured with PocketPC, no? I bought several games on PPC that I am no longer able to run, because lack of emulators (if any, please mention some), but mostly because many games and software at the time required an activation code which is no longer available because the companies/authors/servers disappeared.
The UI is in a separate version of the emulator, launched with the little "UI" button in the top right corner of the image panels (e.g. https://floooh.github.io/tiny8bit/kc85-ui.html?type=kc85_4).
The UI is updated once per 60Hz frame, so you only see a per-frame snapshot of the microchip pins which on its own isn't that useful yet except for a nice blinkenlight effect, but it will make a lot more sense once a step-debugging window is added. This will let you inspect the pins after each CPU instruction (still not as accurate as the emulation, which is running with machine-cycle granularity on Z80, and clock-cycle granularity on 6502 machines.
The emulators are written in C(99), with some platform-specific bits written in Objective-C and Javascript, and in C++ for the UI parts (since Dear ImGui is implemented in C++). Apart from the WebAssembly version, Win32, Linux, OSX and iOS is also supported, but you need to compile those yourself :)