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A comment on Benchmarking division and libdivide on Apple M1 and Intel AVX512. Parent comment

Re:Benchmarking division and libdivide on Apple M1 and Intel... by monocasa on Wednesday May 12, 2021 @10:26PM (#27137762)
Their AMX instructions, and those decompress instructions you found in user space are the exact kinds of things even regular architectural license holders aren't allowed to do, even hidden behind a library.

They very clearly have a special, Apple-only relationship with ARM.

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Re:Benchmarking division and libdivide on Apple M1 and Intel... by marcan_42 on Thursday May 13, 2021 @12:26AM (#27138406)
AMX is available in userspace, but only used by their Accelerate.framework library. Apple does not document or expect them to be used by any apps, and I expect they'd reject any App Store submissions that use them, as I doubt they guarantee their continued existence in their current form in future CPUs.

FWIW, the compresssion instructions are used by the kernel, and I don't even know if they work from userspace. I've only ever tried them in EL2.

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Re:Benchmarking division and libdivide on Apple M1 and Intel... by comex on Wednesday May 12, 2021 @11:07PM (#27137992)
Sure. But the M1 doesn't drop backwards compatibility with existing (userspace) code, which nine_k arguably suggested it did.
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Re:Benchmarking division and libdivide on Apple M1 and Intel... by spacedcowboy on Thursday May 13, 2021 @01:26AM (#27138723)
They co-founded Arm. It’s not too surprising that they know the right people there...
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