A Playdate with the N64 MiSTer core (aka the 'I'm on a boat' issue)

A new interview with the dev behind the MiSTer's most-anticipated core, and an overview of the Playdate's emulation scene.

A Playdate with the N64 MiSTer core (aka the 'I'm on a boat' issue)

Hey ROM readers, if you’re reading this on Sunday, September 10th I’m likely on a boat, squeezing in a mini vacation with childhood friends between a hectic month of work and family obligations. Travel has left me without any real time to put together a big issue of ROM this last two weeks, so this is going to be a bit of a shortie. But there’s still some good stuff here. First, I finally got my hands on a Playdate, as you can see, which gave me an excuse to dive into what the emulation scene’s like for the bittiest of handhelds. You may not be surprised to learn that it’s lagging behind the selection of solitaire, dice, and crank game options. But it does exist!

Second, we’ve got a check-in with one of the most-anticipated projects in the MiSTer scene right now: the N64 core. How far along is it? Can it play games? What’s still in store? That’s the second half of our Big Two this issue!

Speaking of the MiSTer, down in the Core Report you’ll see some juicy news about a new Sega Genesis core, and there’s some hot stuff in the Translation Station this week, too. Enjoy the round-up — I’ve got Painkillers to drink and BBQ brisket to eat to close out this summer. 🌴

The Big Two

1. Can the Playdate emulate a Game Boy?

Gosh if the Playdate isn’t the cutest little thing. The first game I bought was Clash Cards, a micro remake of Final Fantasy IX’s Tetra Master that feels like it exists purely for me. I love it. But we’re here to talk about emulation, and that was the second thing on my mind — can this thing run Game Boy games, or what?

It seems like a perfect pairing, but the answer seems to be not yet. But not yet isn’t no, and there’s actually a lot of interest and some development work going into figuring out how to pull it off. There actually is a functional emulator already, called Playboy, but functional comes with a big fat asterisk. There’s no audio support, and the emulator only runs at playable framerates in the Playdate’s PC/Mac-based simulator. On real hardware, well, hope you like Tetris at 1 fps. The last Github commit was a full year ago.

But that’s not the end of the Playdate Game Boy story. This fairly active forum thread includes several developers talking about the main performance challenges of Playdate emulation and how to overcome them. “It seems these projects all hit a performance wall around 30-40 fps (the Game Boy's true speed is 59.7 hz),” writes programmer NaOH. They’ve taken a crack at writing a fast JIT compiler; the Playdate CPU is certainly fast enough, but it’s not the only bottleneck, so it’s still TBD if that will be the eventual solution.

“Efficiency around memory usage is everything on Playdate,” says developer Dustin. “The amount of work most emulators do per pixel just doesn't seem to fly on device.”

The Playdate’s 50Hz screen is another complication: “DO NOT DO INTERLACING in the current display driver version,” writes developer SonoSooS. “Do 30Hz screen update instead with a flick between even/odd frames between every second or half a second, full screen updates are twice as fast at worst case.”

SonoSooS says the emulator they’re working on won’t see the light of day until 2024. It seems like such a perfect match, it’s hard to imagine the Playdate won’t eventually be able to run Game Boy games on its lil black and white screen, but the interesting bit will be seeing how we get there.

Game Boy isn’t the only console devs are fiddling with on the Playdate, of course — there’s also octobinz’s attempts at getting the Sega Genesis to run, and another project for the NES. Again they’re possible in the simulator, but on real hardware performance is going to be a massive challenge. I think the deciding factor here will be whether devs lose interest in the Playdate beyond that initial experimentation, because it really is a novelty device with a small base of only ~50,000 owners.

2. A quick update with N64 MiSTer developer Robert Peip

In April 16th’s ROM, I spoke with programmer Robert Peip (FPGAzumSpass) about his recently announced MiSTer core for the Nintendo 64, which was early in development. At the time, Robert explained that his development process is to first write a software emulator that serves as a very thorough, examination of how the system works. Accurate, but very slow — it’s not really meant for playing, but is very useful for testing.

"Now I can use it for plenty of things, e.g. compare a rendered image against the emulator and automatically check for wrong colored pixels,” Peip told me this week, when I asked him to catch me up on his progress. “In the emulator I can test things in seconds, when for the FPGA every build takes more than 10 minutes.”

Writing the emulator was completed some months ago, so Peip is now deep into the work of actually writing the code for the MiSTer’s FPGA hardware. It’s exciting progress.

“I think about 70% of the total code is written. All the main chips are there, but some are still missing subfunctions. When everything is written down however, that doesn't mean that everything works, so I would say the project schedule overall is maybe at 30% or so. There will be bugs and more research to be done.”

If you’re interested in the more technical list of what’s still on the to-do list, here’s the breakdown:

“For the RDP there is still the LOD/MipMap functionality and Dithering, both completley missing. Also a bunch of smaller functions like multitexturing and special blending modes.

Then the Video out is currently only a hack, it needs to be done with the correct PAL/NTSC clock, Anti-Aliasing, Gamma and all the features. We also still need all controller add on features: Rumble, Controller Pak and Transfer Pak.

And the CPU is still missing the TLB and some Cache functions.”

While the biggest bits of the job are already done, all these remaining pieces will add up to take “significant time” to complete, Peip says. So the finished core is still a ways off — hence his estimate that the overall project is only around the 30% completion mark. I’m hoping that means a beta is in the cards before too long, though. Obviously there will be many bugs to fix on the road to getting the N64 library in fighting shape. I see visions of Ogre Battle in my future…

Patching In

  • The little things matter - PCSX2 now has a hotkey to toggle the on-screen display on or off. Also, refractionpcsx2 fixed a graphical glitch in Dragon Quest VIII by allowing the emulator to “check for primitive gaps to allow reverse draws starting from the bottom.” No idea what that means, but: nice.
  • Wii U emulator Cemu now has a built-in utility for pairing with Wiimotes, as well as better Wiimote support on Linux and MacOS which lagged behind Windows.
  • New mammal on the block Panda3DS has been making fast progress, and just hit a .5 beta stable release this week. Each release includes more game compatibility, though this one also includes a more significant update: “Custom red-panda-themed mii faces.”

Core Report

  • MAME 0.258 dropped at the end of August, bringing with it improvements to early Macs, the SGI workstation, and Namco’s System 12, if you specifically want to play Derby Quiz My Dream Horse. Another new bit of working software: Inspector Gadget - Operation Madkactus. Aren’t videogames beautiful?
  • MiSTer gets a new Genesis core - Nuked-MD has been integrated into the MiSTer project, which lead dev sorgelig says “is a replica of real hardware (unlike functionally similar Genesis core).” Nuked-MD was created with decapped Sega Genesis chips, with the goal of being a cycle-accurate emulator. Now that it’s implemented into the MiSTer, I expect a lot of eyes on the project evaluating whether it truly is hardware perfect, but sorgelig clearly saw it as an improvement over the MiSTer’s existing Genesis implementation, which is a strong endorsement.

Translation Station

  • GBA adventure game Zero One SP has a translation in the works - Translator Traceytrace has previously tackled a couple Zoids games for the GameCube and DS, and has now decided to tackle Zero One SP. A couple months ago YouTuber Bowl of Lentils made a video about it titled “The GBA’s ‘Largest Adventure Game’“, going into how it begins as a high school visual novel and expands from there into a wildly sprawling sci-fi adventure. Sounds neat.

    Traceytrace is open to assistance in the form of grammar edits and J>E suggestions, so hit the link above if you’re interested in following along and helping. This one could be a long way off from completion, but it’d be real cool to see such an ambitious GBA game get its due outside Japan. (Credit to Time Extension for this one)

  • Satellaview’s Dynami Tracer surfaces - Another game I’ll happily admit I’d never heard of, but this one from Squaresoft 😮 Translator krokodyl says the translation is finished and will be live on the linked page imminently. Dynami Tracer was originally a satellite download game, but the released rom will play nice with SNES emulation. It’s apparently a wacky space race adventure built in the Chrome Trigger engine (!?) but sans combat.

Good pixels

Sticking to the Playdate theme, these two shots are from an experimental Sega Genesis emulator for the Playdate by developer Octobinz. It may not ever be able to run this well on real hardware (these are via the Playdate simulator), but damn that B&W look is cool.

See y’all on the streets (of rage).