https://www.eejournal.com/article/whats-inside-apple-silicon...

Can you provide some more information on this? I would love to be able to hit them on this, as this would actually be really upsetting to a lot of people I know who work on toolchains.

The rumor I've heard is that Apple is keeping their custom extensions to the ISA undocumented in deference to ARM's desire not to have the instruction set just completely fragment into a bunch of mutually incompatible company-specific dialects.

It's worth noting that the article you link predates the public release of the M1 by a good 10 months. Given how secretive Apple tends to be about these sorts of things, one can only assume that it was based almost entirely on rumor and conjecture.

But it's not really about trying to prevent anyone from discovering that these opcodes exist. It's about trying to discourage their widespread use. If it's undocumented, then they don't have to support it, and anyone who's expecting support knows to steer clear. That gives them more freedom to change the behavior of this coprocessor in future iterations of the chip. And people can still get at them, because Apple uses them in system libraries such as the OS X implementation of BLAS.

The second I have no doubt you are correct - I know of several organizations that have licensed ARM just to ensure they have a long term plan to get more without the CPU going obsolete again (one company has spent billions porting software that was perfectly working on a 16 bit CPUs that went obsolete - there was plenty of CPU for any foreseeable feature, but no ability to get more). These want something standard - they are kind of hoping that they can combine a production run with someone else in 10 years when they need more supply and thus save money on setup fees.

The first is a lot harder. The big players ship a lot of CPUs, and they the volumes to make some customization for their use case worth it. However I don't know how to get real numbers.