PICO-8 is a fantasy game console from Lexaloffle which allows you to create, edit, share and play small games in a virtual console.
yocto-8 is a PICO-8 implementation that aims to run unmodified games.

That's the plan anyway -- see the current progress.

The main implementation goals are:

• To reach good PICO-8 compatibility
• To be as fast as possible, and to minimize the RAM footprint as much as reasonably possible
• To be generally portable to platforms with a high quality C++20 toolchain

The current plan is not to be a PICO-8 devkit, that is, it will not provide any editor tools.

yocto = pico².

With some modifications, some demos and games run. We're far from good compatibility, especially on real hardware.

It is possible to build and run yocto-8 on the desktop which is currently the preferred way for implementing new API features due to facilitated debugging and allowing a faster development cycle in general. The main target remains the embedded implementation.

This is currently in an early stage: there is no user-friendly way to get this working yet and most cartridges will not work.

A significant problem is the reliance on a hack that enables mapping of SPI RAM.
At the moment, this hack is very slow and may compromise the usage of the RP2040 for a real handheld project. Many games and demos rely on using way more memory than the RP2040 SRAM could provide no matter how many optimizations are done.
There is a lot of room for optimization for the RAM hack routine. It is currently not known what real world performance can be theoretically reached.

There are (uncertain) plans to design a real handheld. The main two contenders are the RP2040 and the ESP32-S3 (which supports QSPI RAM), but there are drawbacks to both of these.

• This does currently only aim to be a pico-8-compatible game runner, not an editor.
• There is currently no plan to support games that require the mouse or extra keyboard keys to function.
• No emulation of "CPU cycles" as calculated by pico-8 is planned for now: Game performance will be limited by how fast the RP2040 can run it. This is usually slower than official pico-8 anyways, but may be faster at some operations, namely draw calls.
• Yocto-8 uses an external SPI RAM chip to provide more Lua memory when the malloc pool limit is reached (pico-8 allows allocating up to 2MB of Lua memory). As this requires expensive emulation on the RP2040, games that heavily allocate may run significantly slower.

• Y8_ARCH=desktop: Desktop (both with a SFML frontend and headless)
• Y8_ARCH=pico: Raspberry Pi Pico based platforms
  • Y8_PLATFORM=asupico: My setup (Pico+SSD1351 display+8MB PSRAM+push buttons)
  • Y8_PLATFORM=picosystem: Pimoroni PicoSystem

Pros:

• ~Instant bootup
• Some extra appeal: hackable firmware and allowing to support a niche specific-purpose device
• Usually lower cost
• It should be possible to drive power draw quite a bit lower

Cons:

• SBCs-based solutions are more general purpose (e.g. cheap emulation handhelds)
• SBCs are more versatile (WiFi & Bluetooth, etc)
• Will probably never be fully compatible with all PICO-8 games
• No editor tools, etc.
• More standard hardware