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Sorry, this is unwarranted alarmism. > The first version of these CPUs will be very Arm compatible, as they are trying to drive adoption to of their silicon.
by klelatti 5y ago
Sorry, this is unwarranted alarmism.
> The first version of these CPUs will be very Arm compatible, as they are trying to drive adoption to of their silicon.
All these CPUs will be Arm compatible, otherwise they will be breaking their license.
> Once there get a leg up they will start adding patented operation to their stuff. And then we'll end up with a fragmented CPU field driven by corporate greed.
Maybe they will add accelerators as Apple has done but Arm compatible code will still run on all these CPUs.
> And because they are not OEMing this hardware, they really have no incentive to be cooperative with the others.
Yes they do because they need Arm code to run on them.
There are thousands and thousands of Arm designs in use and they _all_ run Arm code as specified by Arm Ltd.
(And yes I know that there is fragmentation in other things that go on the SoC but that is a different point).
- xyzzy_plugh 5y agoYou can definitely get a license that allows you to go hog wild and make breaking changes. I believe both Apple and Google pay for that. But it doesn't help anyone to fragment too much.
- klelatti 5y ago> You can definitely get a license that allows you to go hog wild and make breaking changes. I believe both Apple and Google pay for that. Reference?
- my123 5y agoThere is some minor breakage, like Apple CPUs enforcing the VHE feature of ARMv8.1-A to be on, and not supporting it being off. But that was like… the sole issue on that front. What you are allowed to do is make extensions with the highest tier of arch licenses, you however cannot break the ISA.
- klelatti 5y agoThanks! Very interesting on VHE.
- saagarjha 5y agoVHE isn't even observable for userspace code, and Apple is very quickly going to drop support for people being in the kernel, so I would argue this probably isn't even that important.
- my123 5y agoFor macOS at Reduced Security, kernel extensions will no longer be supported. fuOS/CustomKC will stay in the long term, and that's what matters for other OSes.
- deleted 5y ago[deleted]
- Cyph0n 5y agoIt’s called an architectural license. There are a few publicly announced license holders, including Apple and Qualcomm. Refer to the Arm wiki page for a list. Probably outdated article on this: https://www.electronicsweekly.com/news/business/finance/arm-adds-architectural-licensee-2015-04/ https://www.electronicsweekly.com/news/business/finance/arm-...
- klelatti 5y ago> Companies can also obtain an ARM architectural licence for designing their own CPU cores using the ARM instruction sets. These cores must comply fully with the ARM architecture. (Wikipedia) That's not going 'hog wild'!
- szundi 5y agoDoes not need a reference as ARM itself is not the whole platform that can be compatible or incompatible. Whoever tried to change CPU/microcontroller finds that not the core itself that matters the most, but the peripherals and the whole stuff as a system.
- klelatti 5y agoWe’re talking about licences for Arm cores.
- deleted 5y ago[deleted]
- m0zg 5y ago> All these CPUs will be Arm compatible At base ISA level perhaps. But there will also be extensions for AI, DSP, media encoding, etc which will be incompatible. You nominally wouldn't have to use those, but the CPU will be nothing special without all that. This problem is already quite pervasive in the ARM ecosystem, and it'll get worse over time. There's no way around this. In a power-sensitive environment the only realistic way out currently is specialized co-processing and ISA extensions.
- klelatti 5y agoYou’re getting completely confused between ISA extensions (very rare) and other functionality on the SoC such as GPUs which are obviously universal and very diverse.