I was once in a meeting with people working on RISC-V architecture, and the subject was RISC-V. I asked a question regarding extensions and compatibility: was there any suggested guidance on how vendors could or should ensure that extensions would be compatible with each other, considering things like data sharing, security, privacy, etc? My understanding is that the answer was that those were good questions, and no guidance existed.
I did some reading after talking with Ron at IWP9. Apparently "Profiles" are the solution to this (these didn't exist to my knowledge when I asked the question) and the extensions still seem to adhere to the semantic simplicity of translating instructions to individual hardware operations. Some of the profiles apparently also prescribe details that aim to prevent the kind of "every SoC is a snowflake" hell that we had with ARM for ages. I am far from an expert in this field, but it seems like there's actually been useful progress here, at least from a specification side. No idea what vendors do. Kind regards, --dho On Sat, Sep 19, 2026 at 3:30 PM <[email protected]> wrote: > > In the following document, http://www.collyer.net/who/geoff/9/9k-riscv.pdf > Mr. Collyer shares very clear opinions on RISC-V. I have thought about > these, and wanted to know more, for quite a while. It now occurs to me that > there may be three different things: > > 1) The RISC-V definition and extensions, > 2) The instruction sets that individual assembly-language programmers choose > to use, > 3) The instruction sets that board manufacturers decide to include in their > products. > > This opinion paper makes it very clear that in the opinion of at least one > person, "proposed and approved extensions beyond IMAFDC, and other additions" > should not be used. If one either happens to agree with this, or accepts the > conclusion for any other reason, obvious questions are the following: Are > any board manufacturers following this advice, and if not.. why? How big > would the community of people wanting such a board have to be to motivate the > creation of it, and how far short of being that big is that community now? > > I should add that I previously did a search on this general subject, and > found the following: > https://github.com/bintukappilgeorge/64-bit-RISC-V-processor-RV64IMAFD-SoC-Design > 9fans / 9fans / see discussions + participants + delivery options Permalink ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/Tbf390d3a51f65cdf-Mb52f32e5922bdd8e73445fc0 Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
