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Comment by tyingq | Hacker News Reader

MIPS64 unless Loongson changed direction recently.

LoongArch is distinct from, but derived from, MIPS64. It's starting to look a little RISC-V-like these days.

There's a short section section about this on Wikipedia: https://en.wikipedia.org/wiki/Loongson#LoongArch

Why the custom arch? If building a CPU is a challenge, then supporting an entire toolchain and ecosystem for it is a whole other level of complexity that isn't necessary or helpful. Moving from being pure MIPS only makes sense if there is some patent issue that you are trying to avoid because you want to sell to foreign markets to raise volume of production.

But then just go with RISC-V, I mean there are legions of ravenous fanboys out there _and_ it's already got support.

So the only thing that makes sense is that you have legacy MIPS clients and machines where either you want a drop-in replacement, or compatibility with them... but also want to piggy back on RISC-V and will end up with a CPU with a split personality.

Why?

"The release shows that domestic CPUs have reached a new height in self-sufficiency and performance. It also demonstrates that China is capable of producing first-class products based on a proprietary CPU structure,"

As this is also kind of one of the responses to the West trying to technology-boycot them (what can be considered now hugely failed and soon, if not already, backfiring..) could also be seen as a feature, and not a problem?! ;)

We'll have to wait until China's ASML stockpile is "old" tech (in 5 years or so), before deciding if the tech embargo has worked. I don't support the embargo, by the way.

It's possible that they looked at RISC-V and concluded that it was unlikely they could achieve their performance goals with that architecture.

As far as I understand it, the new Loongson CPU and the Asus mainboard are available commercially today. I don't think there are any RISC-V CPUs with compare single-core performance.

Or they've been at it for a number of years and predated risc v.

If you want to add features to MIPS who would you even talk to?

And afair LoongArch started before RISC-V was as popular as it is today.

They started with MIPS III, moved to MIPS64 before incrementing on that to create their "own" ISA.

If you _really_ want to win a horserace, betting on several horses it's not a bad idea.

When LoongSon started the transition from MIPS to their own ISA, important parts of the RISC-V standard such as the Vector, Crypto and Bitmanip extensions weren't yet ratified.

Their long-term strategy is to support other ISAs through binary translation, thereby skirting around IP issues associated with them and making the hardware ISA matter less anyway.

I remember a lot of noise when Loongson added support for their CPUs to Go. Go already had MIPS64, so if they had to do porting work, it might not be just a MIPS clone. I haven't looked at either architecture in detail for a long time, though.

What operating system would be run by PCs using this chip? Are there existing operating systems that support LoongArch?

Linux (https://en.wikipedia.org/wiki/Loongson#Operating_systems)

Hmm no reference to the OpenBSD port. https://www.openbsd.org/loongson.html

This is for the old MIPS based machines, the new ones have a custom ISA called LoongArch

NetBSD may? If not, it probably wouldn't be a terrible lift to get it running there.

NetBSD development is pretty stagnant these days, I doubt they have much support for new machines

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