After 15 great years at Arm, I’m making a change.

I have learned about how processors work, how they are designed and how they are verified. I have learned about how architectures are designed and how hard it is to change things you get wrong.

I have learned how you nurture the tools and software ecosystem, where you compete and where you choose to let others build their businesses. I have worked in a company that aims to “be Switzerland”, and watched the internal dismay and rapid correction the one time we deviated from that.

I have worked on compilers, runtimes, vector architecture, VLIW, parallelism, software defined radio, DSP, trace, formal verification and security.

And today is my last day at Arm.

I will miss the people I worked with and working on the most widely deployed processor architecture in the world.

But I am looking forward to what is next.

When I posted the above to Twitter, I got a bunch of questions. So here are some answers:

• Arm has teams in place to carry on some of the work I have done there: creating and testing formal architecture specifications; and formal validation of processors against these formal specifications.

  These teams have actually owned this work for several years. That is a commmon pattern in industrial research: if a project is successful, teams grow to strengthen, maintain and extend the project and the people that created it gradually move on to other things.

• Over the last three years or so, I have spent about half of my time worrying about what would happen if Arm committed to using formal processor specs to generate everything. This would remove a lot of the redundancy in the specification development process: no second model to compare against, less experience/skill needed to create tests, simulators, documentation, etc. (My “Who guards the guards?” paper and my recent blog posts are part of what came out of that.)

• I do know where I will be working next.

  The next job will involve formal specification and verification. But, first, I have a nice period of “funemployment” to decompress and catch up before I start.