Let me clarify that this is a proposal for a particular implementation of RISC-V, and per a post on the mailing list yesterday the first cut of the tagging exte

Let me clarify that this is a proposal for a particular implementation of RISC-V, and per a post on the mailing list yesterday the first cut of the tagging extension will be released very soon. It's intended primarily for security, essentially to allow hacks to let our current C type code bases to run ... less insecurely. It was proposed to allow the 2 tag bits to be used for other things like type and GC tagging, which is why I'm personally interested in it.