[Someone]

"the license will not permit them to alter the architecture it's all or nothing"

Can you give a reference for that? As far as I know, Apple has an architectural license that allows them to ship anything that passes a test suite. Depending on the way the test suite is specified, that may not rule out shipping a superset of ARM, for example with a few extra instructions.

One that I _think_may_ be useful is one to load values from tagged pointers (caveat: I know little of CPU architecture)

[gchadwick]

> Can you give a reference for that? As far as I know, Apple has an architectural license that allows them to ship anything that passes a test suite.

I can't find one actually, so perhaps I am wrong. If it strictly based upon the test suite then maybe it's sufficiently thorough that interesting alterations are effectively impossible (e.g. it could test you get invalid instruction exceptions when you feed in unused bits of instruction encoding space, preventing you from adding any).