[eschaton]

It would in light of decades of case law prior to Google v. Oracle. An instruction set itself is not protectable IP, only descriptions and implementations are.

What restricts new implementations are:

1. Existing legal agreements, eg if you agree in a contract that you will treat an instruction set as protectable IP, you’d be violating the contract. (Assuming the contract is valid.)

2. Patents, if you need to violate a patent to implement an instruction set then you need to license or wait out the patent, or figure out a way to work around it.

I believe both of these were at issue in Intel v. AMD, since AMD was initially a licensed second source, and Intel thought you couldn’t implement the Pentium instruction set without violating its patents.

[pjmlp]

Which in the end is what allowed AMD to come up with AMD64 and torpedo Intanium efforts.