[hajile]

There's a cross-license agreement in place there that would certainly cover such case -- even if they were ruled to be implicit.

[stingraycharles]

This is important: this shows that AMD and Intel agree that these instruction sets are indeed protected and should be licensed.

[pgeorgi]

And yet there's fx!32 (WinNT for Alpha), x86emu (of XFree86), Bochs, VMware, parallels, Plex86, QEMU plus numerous other implementations of i386+ in software (one of them shipping in Windows 7 and newer to run PCI Option ROMs) where nobody seems to care too much.

OTOH, ARM was rather adamant about not wanting to see ARM instruction set implementations in software for a long time.

Either they saw the value in these emulators existing so that changed their minds - or somebody didn't let themselves be bullied into compliance: just because a company threatens you with lawyers doesn't mean they actually have a case.

[ghaff]

Interfaces in general have been protected. Certainly mechanical interfaces can be. But it's usually protected through patents in the physical world.