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Arm is canceling Qualcomm's chip design license

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Re: Arm is canceling Qualcomm's chip design license

#181

Post by creshal »

SushiHippie wrote: post #178

Because of all the discussions in the comments about ARM and RISC-V, could someone explain to me the difficulties of designing a chip for a new ISA? I'm wondering because to me as a layman it sounds like it's 'only' a different language, so why is it not that easy to take already existing designs and modify them to 'speak' that language and that's it? Or is an ISA more than just a different 'language'? Or is hardware…

> Or is an ISA more than just a different 'language'?

It tends to be more like going from C89 to Haskell. You're not just switching the keywords around, but also fundamental architectural concepts. There's still some parts you can recycle and some skills that transfer, but less than you'd like.

> Or is hardware not really the biggest problem, but rather Software like compilers, kernels, etc.?

That's the next problem. Kernels, device drivers, support hardware, a lot of low level stuff needs to be adapted, and even a company the size of Qualcomm doesn't necessarily do everything inhouse, there will be lots of external IPs involved and all those partners need to also be willing to migrate over to a different ISA.

Re: Arm is canceling Qualcomm's chip design license

#182

Post by [deleted] »

SushiHippie wrote: post #178

Because of all the discussions in the comments about ARM and RISC-V, could someone explain to me the difficulties of designing a chip for a new ISA? I'm wondering because to me as a layman it sounds like it's 'only' a different language, so why is it not that easy to take already existing designs and modify them to 'speak' that language and that's it? Or is an ISA more than just a different 'language'? Or is hardware…

[deleted]

Re: Arm is canceling Qualcomm's chip design license

#183

Post by eggsome »

brucehoult wrote: post #14
nahnahno wrote: post #7

Earlier quoted context omitted.

I don’t think they have a plan B. Architectures take half a decade of work. Porting from risc-v to arm is not a matter of a backup plan, it’s that of a very costly pivot.

Qualcomm have a Plan B. This time last year they were all over the RISC-V mailing lists, trying to convince everyone to drop the "C" extension from RVA23 because (basically confirmed by their employees) it was not easy to retrofit mildly variable length RISC-V instructions (2 bytes and 4 bytes) to the Aarch64 core they acquired from Nuvia. At the same time, Qualcomm proposed a new RISC-V extension that was pretty muc…

What do you mean by Plan B? From what you've just said it sounds like their proposal was rejected, so there is no plan b now?

Re: Arm is canceling Qualcomm's chip design license

#184

Post by MindSpunk »

gardaani wrote: post #179
IshKebab wrote: post #148

Earlier quoted context omitted.

1. That doesn't mean you can just slap a RISC-V decoder on an ARM chip and it will magically work though. The semantics of the instructions and all the CSRs are different. It's going to be way more work than you're implying. But Qualcomm have already been working on RISC-V for ages so I wouldn't be too surprised if they already have high performance designs in progress.

> That doesn't mean you can just slap a RISC-V decoder on an ARM chip and it will magically work though. Raspberry Pi RP2350 already ships with ARM and RISC-V cores. https://www.raspberrypi.com/products/rp2350/ It seems that the RISC-V cores don't take much space on the chip: https://news.ycombinator.com/item?id=41192341 Of course, microcontrollers are a different from mobile CPUs, but it's doable.

That's not really comparable. Raspberry Pi added entirely separate RISC-V cores to the chip, they didn't convert an ARM core design to run RISC-V instructions.

What is being discussed is taking an ARM design and modifying it to run RISC-V, which is not the same thing as what Raspberry Pi has done and is not as simple as people are implying here.

Re: Arm is canceling Qualcomm's chip design license

#187

Post by dzaima »

creshal wrote: post #181
SushiHippie wrote: post #178

Because of all the discussions in the comments about ARM and RISC-V, could someone explain to me the difficulties of designing a chip for a new ISA? I'm wondering because to me as a layman it sounds like it's 'only' a different language, so why is it not that easy to take already existing designs and modify them to 'speak' that language and that's it? Or is an ISA more than just a different 'language'? Or is hardware…

> Or is an ISA more than just a different 'language'? It tends to be more like going from C89 to Haskell. You're not just switching the keywords around, but also fundamental architectural concepts. There's still some parts you can recycle and some skills that transfer, but less than you'd like. > Or is hardware not really the biggest problem, but rather Software like compilers, kernels, etc.? That's the next problem.…

I'd perhaps put ARM vs RISC-V closer to like C# vs Java (or maybe JS vs Python) - on a high level rather similar, but a majority of the specifics don't really line up (especially at the uop level requiring dumping a bunch of previous optimized cases, and adding a bunch of new ones).

Re: Arm is canceling Qualcomm's chip design license

#188

Post by billti »

happymellon wrote: post #176
javawizard wrote: post #147

Earlier quoted context omitted.

Apple has (to a first approximation) a royalty-free license to ARM IP by virtue of the fact that they co-founded ARM - so yes, Qualcomm is most likely paying ARM more than Apple is.

Just to clarify for those that don't know ARMs history, Acorn were building computers and designing CPUs before they spun out the CPU design portion. Apple did not help them design the CPU/Architecture, that was a decade of design and manufacturing already, they VC'ed the independence of the CPU. The staffing and knowledge came from Acorn.

> Apple did not help them design the CPU/Architecture

I believe they had a big hand in ARM64. Though best reference I can find right now is this very site: https://news.ycombinator.com/item?id=31368489

Re: Arm is canceling Qualcomm's chip design license

#189

Post by yalogin »

hajile wrote: post #52
mushufasa wrote: post #36

Qualcomm is known for having a particularly aggressive & hardball-style legal department to enforce its patents on core telecom IP. I believe the most likely outcome is they just settle the dispute here. Arm fighting hardball with hardball. Which would not really affect the ecosystem of phones using Qualcomm arm chips, it would just change the margins / market cap of Qualcomm. Yes, longterm Q might invest in their ow…

Qualcomm doesn't have nearly as much to lose as ARM does and they know it. Qualcomm is almost certainly ARM's biggest customer. If ARM loses, Qualcomm doesn't have to pay out. If ARM wins, Qualcomm moves to RISC-V and ARM loses even harder in the long-term. The most likely outcome is that Qualcomm agrees to pay a slight bit more than they are currently paying, but nowhere near what ARM is demanding and in the meantim…

Moving to a whole new architecture is really really hard, no? The operating systems and applications all need to be ported. Just because Qualcomm cannot be friends with arm, every single Qualcomm customer from google to some custom device manufacturer needs to invest years and millions to move to a new architecture? Unless I am fundamentally misunderstanding this, it seems like something they won’t be able to achieve.

Re: Arm is canceling Qualcomm's chip design license

#190

Post by PhilippGille »

Most comments here seem to think that Qualcomm has to settle or switch to RISC-V. But from my understanding the article is only about their license to design custom chips with ARM IP, not about using ARM's designs.

For example the Snapdragon 8 Gen 1 uses 1 ARM Cortex-X2, 3 ARM Cortex-A710 and 4 ARM Cortex-A510, which are ARM designs. Their latest announced chip though, Snapdragon 8 Elite, uses 8 Oryon cores, which Qualcomm designed themselves (after acquiring Nuvia).

So is Qualcomm not still able to create chips like the former, and just prevented from creating chips like the latter? Or does "putting a chip together" (surely there is a bit more going into it) like the Snapdragon 8 Gen 1 still count as custom design?

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