Every new feature set (the many SSEs, AVXs, and others) is patented. But newer processor features (like AVX) don’t “renew” the patents on the older features. So when AVX-512 was patented, it didn’t change the expiration dates for AVX2 and prior.
The base requirements for x86-64 mandate SSE2 IIRC. Those patents expired this year, so Apple was now able to release an x86-64 “emulator” without negotiating patents.
Huh. Is AMD paying licensing fees for the privilege of implementing the AVX and AVX2 instruction sets? It seems weird and anticompetitive that patents are granted for what amounts to an API.
(Do you have links or identifiers for the specific patents, by any chance?)
The situation with AMD is a bit complicated. Basically, there was an antitrust lawsuit led by AMD years ago, and as part of the settlement, Intel and AMD would share patents to allow collaboration. I can’t recall the actual specifics though.
As for patents, I don’t, but someone else here linked in the one for FMA[0]. It’s a bit more complicated than just an API, but it seems broad enough that anything implementing that API would be covered. But IANAL.
The base requirements for x86-64 mandate SSE2 IIRC. Those patents expired this year, so Apple was now able to release an x86-64 “emulator” without negotiating patents.