MIPS Goes Open Source

I guess the thing that has put me off of RISCV is The emphasis on for peripherals, they’re just doesn’t seem to be a lot. Yeah, there’s a peripheral bus, And I’m sure it works great but…

This is where I could see MIPS going open source to have a serious advantage. There are people out there that already have experience with how MIPS peripherals should work.

RISC-V may have hastened its demise, but the writing was on the wall for a long time.

Just minus a lot of the "legacy baggage"

> Linley Gwennap, principal analyst at the Linley Group, told EE Times, “MIPS is certainly behind RISC-V in mindshare in the open-source community.” He noted that MIPS was “unable to make this move sooner due to its various ownership transitions.”

The people who think "there's still time" completely misread the situation. Same with the "maturity" argument.

None of these plans are a surprise to anyone. MIPS has been working on this for quite a while.

Yet they have exactly zero announcement partners saying they plan on doing something with it.

That's because none of them care at this point.

(Also, it will take a year or two before any of this is real in a way a partner might be able to use/contribute to/care about etc)

The only meaningful thing that will happen here is people will try to use it to leverage the stuff they want out of risc-v to happen.

I'm very biased against companies/tech projects that go open source as a last ditch attempt to stay in competition when it's clear that an open source solution is gaining steam/mindshare -- it always seems disingenuous.

And that was in part what has killed them.

ARM only got so far thanks to their no questions asked attitude. I heard from people from Chinese fabless companies of ARM DHLing usb sticks to them in the early A8/A9 era, and flying support engineers to them the same day.

Comparing MIPS to them, they had an obviously bad attitude.

First, they barely sold complete solutions, nor worked on their integration (DMA controllers, memory controllers, bus interfaces and PHYs)

Second, they were compete slowpokes. People are telling of them spending weeks to reply to very clear licensing applications, and them nor being able to say a word without going through their lawyers. You were essentially speaking not with sales, or engineers, but their legal department.

Third, patently bad support.

Only when they hit the terminal stage, they seemed to notice that they were doing something wrong

[1] "Synthesis of Processor Instruction Sets from High-Level ISA Specifications" IEEE Transactions on Computers 2014, 63(6), 1552-1566

[2] https://deepspec.org/entry/Project/Kami

Eh... In Sun's case they were acquired by Oracle. I don't think that will have improved the situation.

You'll see lots of bad anecdotes about Oracle here & there. You might wonder "huh, is all that really true?" Well, I've dealt with Oracle. I have yet to see something bad about them that didn't jibe with my own experience: I won't give info that might dox me, but there was a fairly visible lawsuit involved.

Well, things change, and if he still thinks about a couple of big vendors, that would fit. But most of the Chinese SoC vendors using RISC-V aren't big nowadays, and most of them probably wouldn't bother with all that corporate memberships and stuff.

SPARC is already open, as in it can be used royalty free and there are open source implementations.

After ARM saw that the sky is not falling on MIPS, they decided to license them their cores as well.

Basically your usual DSP fare.

ARM has a similar extension; see https://en.wikipedia.org/wiki/ARM_architecture#DSP_enhanceme... for a reference to it, or http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.... for details.

I don't think that RISC-V has a DSP extension yet; they are still working on nailing down their SIMD/vector extension story.

Does the MIPS ecosystem have an equivalent to coreboot?

It still isn't SPARC ADI, but at least we might get some additional safety along the OS stack that way.

The MIPS DSP ASE extends the base instruction set with certain instructions applicable to various codecs of the day that the ASE was defined for. It's essentially extending a general purpose cpu to efficiently perform DSP like tasks.

Transmeta's founder is working on RISC-V AI/ML chips at Esperanto.

The R3051 (used in the PlayStation 1) was a derivative of the R3000A (which MIPS should have the rights to) made by IDT. I don't think MIPS have the right to the modifications.

The R4300 (A derivative, the NEC VR4300 was used in the Nintendo 64) was designed by Quantum Effect; I think whoever owns what's left of them would own the HDL, if it's still around.

The R5900 (used as the core of the PlayStation 2's Emotion Engine) was designed by Sony and Toshiba; I'm pretty sure Toshiba have the rights to it.

It's worth noting that, as the article points out, MIPS remains patent encumbered, the ownership situation of these patents is itself quite complex, and all in all, it's not quite clear how the new "Open" licensing will work.

I would take everything with a grain of salt until it is truly open sourced and then revisit the question.

The RISC-V instruction set family does benefit from the decades of research since MIPS was first created.

Also, a lot depends on the ecosystem surrounding whatever MIPS cores are available. Memory crossbars, interrupt handling, etc. There's a lot that goes into a system-on-chip.

However, it's now at the point where there are shipping RISC-V Linux distros, it's supported in GCC and LLVM out of the box, there are more than a dozen open-source RISC-V cores (https://riscv.org/risc-v-cores/, several of which are actually parameterized families of cores), and there are companies like SiFive offering commercially supported proprietary cores. There is hardware that has shipped from multiple different vendors, and that likely means that there are a number of others where it's fairly far in the pipeline.

With MIPS being behind Intel on the desktop and server market, behind ARM on the proprietary embedded core front, and behind RISC-V on the open source ISA and cores front, it's a bit hard to see why someone would buy MIPS who hasn't already invested in it.

If you want something more well established with a wider variety of cores available to purchase, you'd go with ARM. If you want something with no ISA licensing fees and even potentially no charge at all for an open source core, you can go with RISC-V.

I suppose there is some chance that MIPS could win some folks over from RISC-V for already having stable SIMD and DSP extensions, and more overall architectural maturity than RISC-V. But given that this seems to just be opening up the ISA without opening up any cores, and right now is a press release without having decided on the governance structure for the project or released any assets, while RISC-V has a number of fairly mature open cores including Rocket, BOOM, RI5CY, and more, and has a governance structure with a number of different companies involved, it seems like it will be a while if ever for MIPS to catch up on the open ISA front.