It's early from a pure legal no-negotiation standpoint, but remember that we're approaching the point (which has gotten surprisingly little coverage to me) wher

It's early from a pure legal no-negotiation standpoint, but remember that we're approaching the point (which has gotten surprisingly little coverage to me) where a lot of core patents on x86-64 will expire. AMD64 was announced in 1999, 2000 saw the spec out, 2003 was the first implementation if I remember right with Opteron, and in 2006 Intel had Conroe out. Even Apple officially dropped support for early x86-64 Macs, it was often due to things like early issues with their EFI implementations or GPU drivers for Intel IGP, not because of some added instruction they were depending on. There were many examples of people doing some hacks to get non-supported versions of macOS to run long after it wouldn't install by default and it would work fine. So in terms of the minimum needed to achieve essentially all the backwards compatibility Apple would care about, it's gotta be pretty close since patent applications and priority dates are typically well before implementations. And even if not everything they wanted was expired, the mere fact of it happening would create leverage for other bits. So it'll be really interesting what they've done, they may well have not merely an emulator but something involving a hardware layer as well. Or I guess maybe they'll just dump BC like some have pessimistically expected, but useful forms of x86-64 becoming open to any player seems like it might be a pretty big deal for the industry doesn't it? As we've reached the flatter part of the S-curve and the ISA lifetime has stretched out far longer then anyone expected at one point, it's actually catching up with old IP law for once. 20 years is a long, long time in tech. But it's not forever, and maybe not so long as it once was even.