openc910 VS PSn00bSDK

> I'm pretty sure that SiFive isn't allowed to sell their RISC-V core designs to any Chinese company already.

The JH7110 SoC from the Chinese firm Starfive uses SiFive's U74 core. Eswin, also Chinese uses SiFive's P550 core in their upcoming EIC7700 SoC.

> All Chinese RISC-V core designs have been proprietary designs thus far.

There is the OpenC910 [1] and OpenXiangShan [2].

[1] https://github.com/T-head-Semi/openc910

Note that the C910 CPU cores used in this chip are in fact open source:

https://github.com/T-head-Semi/openc910

(C920 is just C910 plus RVV draft 0.7.1 vector unit which pretty much no software uses anyway, sadly)

The Milk-V Pioneer uses a C910 CPU, which has been open sourced by t-head: https://github.com/T-head-Semi/openc910

More precisely, a Chinese university assembled a rack containing 48 [1] commercially available SBCs [2], each with a Chinese-designed and made SG2042 SoC with 64 C910 CPU cores. The C910 was designed in China in 2018/19 and open-sourced in October 2021, on Microsoft's github site.

https://github.com/T-head-Semi/openc910

The SG2042 is the most powerful RISC-V SoC available today.

In which direction is the technology transfer going?

[1] or possibly 24 dual-socket boards, shown at the RISC-V Summit China in August

[2] get your own here https://www.crowdsupply.com/milk-v/milk-v-pioneer

For "coming down the pipeline" they're essentially free.

Today, the c910 is an Apache 2, hardware proven out of order core on GitHub here https://github.com/T-head-Semi/openc910 a little slower than an RPi3's core.

Here is the source code* for the CPU:

https://github.com/T-head-Semi/openc910

* AFAIK they didn't opensource the pre ratification vector extension implementation they ship with the taped out chip.

The source RTL for the roughly Arm A72-equivalent cores used in this were open-sourced several years ago.

https://github.com/T-head-Semi/openc910

The same cores are used in the 64 core SG2042 workstation/server SoC.

It's a shame, because it was the best design from ARM; they're now focusing on Cortex-A7x and Cortex-X, which aren't anywhere as power efficient[0].

Meanwhile, their revised Cortex-A57 has been surpassed in performance/power/area by several RISC-V microarchitectures, such as SiFive's U74[1], used in the VisionFive2 and Star64, or even the open source XuanTie C910[2][3].

0. https://www.youtube.com/watch?v=s0ukXDnWlTY

1. https://www.sifive.com/cores/u74

2. https://xrvm.com/cpu-details?id=4056743610438262784

3. https://github.com/T-head-Semi/openc910

The original PlayStation's main SoC (which is incidentally about 30 years old at this point) included a trimmed down JPEG decoder [1] meant to be used for video playback. It still relied on the CPU to handle Huffman decompression [2], but it allowed that otherwise anemic 33 MHz MIPS core to push 320x240 video at 30fps.

[1] https://psx-spx.consoledev.net/macroblockdecodermdec/

[2] https://github.com/Lameguy64/PSn00bSDK/blob/master/examples/...

That post introduced me to both WebGL and reverse engineering back in the day. I remember reading it years ago and asking myself "seriously, is it that easy to do 3D in a browser???". The web as an app platform is not without its issues, sure, but for quick prototyping being able to just write some JS and have instant access to plenty of APIs is awesome.

Last year I decided to finally break out of the browser and get into actual PS1 homebrew. Unfortunately the state of the scene wasn't, and to some extent still isn't, that great: most homebrew games are still made using what's basically a modded version of the original Psy-Q SDK, which is rather limited in many ways. I started contributing to an open-source PS1 SDK instead [1] by first adding a dynamic linker, then revamping the build system entirely and now building a custom high efficiency FMV playback library (totally not inspired by pl_mpeg of course) that combines the hardware accelerated MJPEG-like decoder with the GPU's alpha blending capabilities. I'm also working with a few other people on reverse engineering one of the most famous PS1-based arcade systems, the Konami System 573.

It's a shame the PS1 isn't receiving the attention other consoles are getting in the homebrew scene. The hardware is architecturally simple yet powerful [2], but I guess nobody wants to fiddle with 120mm polycarbonate circles anymore.

[1] https://github.com/Lameguy64/PSn00bSDK

For coding I used PSn00bSDK .

From what I was able to gather the lack of attention for PS1 is mainly due to lack of usable SDK but there is now https://github.com/Lameguy64/PSn00bSDK which made me go this rabbit hole. The demo you shared is nuts tbh.

Thankfully though there is a work-in-progress unofficial SDK that is far easier to set up and more optimized than the Sony crap. It's still in its early stages, but you can already do a lot with it. Anything not covered by the SDK is of course still accessible directly by manipulating hardware registers, just like Arduino.