Profiles are rolled up collections of RISC-V extensions[1]. RVAxx defines a set of standard extensions you can expect to be present in "application processors" (which is fairly loosely defined but is basically non-embedded stuff that you might run a full Linux on.)
Oh nice, recently I had some question about RISC-V extensions and iirc I found your article and it was the one that explained it the best. Thanks for the write up! You helped a minimum of one Person enjoying their journey through the ecosystem :-)
I believe I was reworking the instruction decoder on my own core and the specification sheet left some open questions
Thanks, it was a lot of fun writing it too. I learned a lot of unexpected things about extensions, including that at the instruction encoding level they are not as distinct as I expected, and that there are just so many of them now.
[1] I wrote a quite detailed paper about RISC-V extensions last year: https://research.redhat.com/blog/article/risc-v-extensions-w...