Wow, this is really great.<p>Here at Berkeley Architecture Research and our spin-off company SiFive, we are working on finalizing version 1.9 of the privileged ISA, which includes a lot of useful features for operating system implementers. This includes a standardized way of performing memory-mapped IO, debug port, and possibility of standalone boot.
It's great to see free and open hardware finally arriving.<p>I've known of RISC-V for a while, and just learned of IBM's efforts to open up their Power Architecture: <a href="https://en.wikipedia.org/wiki/OpenPOWER_Foundation" rel="nofollow">https://en.wikipedia.org/wiki/OpenPOWER_Foundation</a><p>Does anyone know of any other free and open processor architectures? I hope we'll see a GPU one soon.
Their comment about the address space identifier field in the MMU setup is absolutely golden. We need to get more practical experience using the architecture to help inform the design from other perspectives.