I am no a fan of apple and their digital golden jail, but I see that move as a way to prepare to jump to risc-v which does not have toxic IP tied to it, once wi have performant risc-v cpus ofc.
1. Apple clearly has no problem with 'toxic' (not sure what that means) IP as long as they have access on acceptable terms - which they clearly do with Arm.
2. Apple were almost certainly one of (maybe the only) lead partner for Arm in developing the A64 ISA - they have had a lot more input into A64 than they have into RISC-V.
3. They design their own architecture - they could have built a RISC-V CPU for the Mac if they'd wanted - they don't have to wait for anyone else.
I don't think RISC-V was ready for prime time when Apple decided to switch away from Intel, which was likely many years before the first M1 products were announced. The RISC-V spec may be stable and fine but you need a whole ecosystem around it to put it to the kind of use Apple wants.
- ARM64 was announced in October 2011. Apple was shipping SoCs based on ARM64 only two years later. Apple can do these things very quickly when it wants to.
- Apple had all the info it would need to base a decision on Arm or RISC-V at the time of the decision to leave Intel. It could have delayed a short while to allow the ecosystem to mature if it had wanted to go for RISC-V.
- It controls a large chunk of the ecosystem anyway (LLVM etc).
I really find the idea that Apple - hardly the most open company in the world (to say the least) - is expected to switch ISAs again to RISC-V for no apparent commercial advantage very, very implausible.
I agree Apple probably isn’t switching to RISC-V any time soon. I’m just not buying the story that they looked at it, could have done it, passed on it, and that’s that.
Even in 2022 it may not be wise to start a huge RISC-V project yet for a company like Apple. It’s not mature enough.
I also agree Apple is not an open friendly company. That’s why I think if they do it then it will likely be loaded with proprietary extensions. So it’s not a matter of simply swapping ISAs, it’s completely rethinking the entire stack. That takes time and expertise. The industry isn’t there yet, not at the scale to support what Apple (and others) would like to do.
Fair enough but in that case what’s missing and stopping them now?
Edit: rereading it sounds like you think Apple might want their own (version of) ISA which is reasonable except they already had huge input into A64 and are adding their own extensions already anyway.
It’s possible Arm is the ISA for the next century, with all the others mere footnotes of history, the same way the 8-but micros have become a dead-end in computing history.
This is a little drop of good in a ocean of bad.