Comment by kjs3

20 days ago

The important point is that using an open ISA allows you to create your own CPU that implements it.

So? You've been able to do that since...computers. Anyone can roll their own ISA any time they want. It's a low-effort project that someone with maybe a Masters student level of knowledge can do competently. When I was in school, we even had a class where you would cook up an (simple) ISA and implement it (2901 bit-slice processors); these days they use FPGAs.

So you got your own processor for your own ISA...that was slow, expensive (no economy of scale) and without a market. But very fun, and open source, at least. And if "create your own CPU that implements it" is what you want, go forth and conquer...everything you need is already there and has been for a long time.

But if your goal is "I want an open source ISA that I can produce that's price and/or performance competitive with the incumbents", well, that's a totally different ballgame.

And there are open source ISAs that have been around for decades (SPARC, POWER, SuperH). These are ISAs that already have big chunks of ecosystem already in place. The R&D around how to make them competitive already exists. Some, like LEON SPARC have even gone into something like production (and flown in space).

So, yes, an open source ISA affords the possibility that we can make processors based on our own ISAs on our own terms. It has even in extremely rare occasions produced a product. But the fact remains, the market hasn't cared in the slightest to invest what's required to turn that advantage into a real competitor to the incumbent processors.

5 comments

kjs3

Reply
LeFantome  19 days ago

Completely wrong.

Yes, you can create your own ISA. But to run what software?

If I create my own RISC-V implementation, I can install Ubuntu on it. Maybe even Steam.

See the difference?

And, the market has responded with a tidal wave of CPU contenders. Like in the rest of the world, not all of them target the highest end portion of the market. But some are choosing to play there. Have you checked-out Ascalon?

And why did Qualcomm pay all that money for Ventana recently? You do not expect them to release high-end RISC-V chips? I mean, they already ship many low-end ones.

  • tw1984  18 days ago

    > And why did Qualcomm pay all that money for Ventana recently? You do not expect them to release high-end RISC-V chips? I mean, they already ship many low-end ones.

    Ventana is an extremely bad example to be used here. It is acquisition price is undisclosed, it could be just some $ for acquiring the team behind it. Secondly, Qualcomm's nuvia acquisition was pretty huge, there is no reason whatsoever to believe the Ventana acquisition is remotely comparable, that proves no one uses RISC-V anyway.

    • LeFantome  18 days ago

      > no uses RISC-V anyway

      Here is an article from a company called Qualcomm from two years ago saying that they had, at that time, already shipped 650 million RISC-V cores.

      https://www.qualcomm.com/news/onq/2023/09/what-is-risc-v-and...

      I notice that the three benefits they flag for RISC-V are: flexibility, control, and visibility.

      I wonder how they felt about "control" after ARM tried to stop them from commercializing the value of their Nuvia acquisition? I wonder if it had anything to do with their next big acquisition being RISC-V based instead?

      I also wonder, why on their Oryon page does Qualcomm never meanion ARM. Not even once. Even to the question, is Oryon x86, they do not answer that it is ARM. Why not?

      https://www.qualcomm.com/processors/oryon

  • kjs3  12 days ago

    Why don't you read what was written instead of being the unthinking RISC-V fanboi in the room. My only point was that the RISC-V license is probably not the biggest factor in its success, since there have been many, many open source ISAs that weren't successful.