You should assume not, because they would've patented everything they can. How old is ARM v4? Is it old enough that patents have expired? You would then need

You should assume not, because they would've patented everything they can. How old is ARM v4? Is it old enough that patents have expired? You would then need to check country by country (where they have filed patents), as each country has its own patent laws. Disclaimer: I am not a lawyer.