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Comment by m-j-fox | Hacker News Reader

I work at a chip company. All of our register definitions and other specifications are created in a machine-readable but human-friendly YAML format.

The specs drive scripts which generate the hardware, test interfaces, C headers for software and the PDF manual we give to our customers. I assume everyone is doing this: how else can you guarantee thousands of pages of documentation and a large API match the product perfectly?

What's new is ARM is giving that internal specification to customers. Makes a lot of sense given their customers are also chip companies with similar practices. I think it's a good idea and everyone should do it.

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What's new is ARM is giving that internal specification to customers.

Not just customers but everyone, judging by the fact that I could just click the links in the post and download the files.

Yes, ARM's architecture licensees (companies allowed to design their own ARM-compatible processors) have had access to the v8-A specs for years. The new bit is making it available so that researchers, companies and individuals can use it in software projects.

This is a lot more than register specifications. It is a specification of the complete functionality of the architecture, written in a format that allows you to generate simulators, do formal verification of RTL code, or probably even generate synthesizable RTL code as well.

I repressed dreams of this so many times along the years I'm tearing up a little.

Probably best not to get too excited about generating hardware from the specs... That would compete with ARM's main source of revenue and my reading of the license is that that is the one thing you cannot do with the spec. But I am not a lawyer.

Or, on a more technical note, my feeling is that if that is what you wanted to do, then you would not start from the style of specification ARM has released.

Licensing aside it is still pretty bold for a fabless IP-only company like ARM to release this level of detailed specification; unlike e.g. Intel or AMD who could still have an advantage even if others made competing implementations, because of their fab technology.

I'd bet there already are clones/semi-clones of ARMs hidden in various obscure far-East ICs which have no user-accessible firmware... we just don't hear about them because the ones we do, would've been sued out of existence. I've seen presumably-unlicensed MIPS cores a lot in those.

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