15:49:48beachI don't understand the question. At the moment SICL is just an end-user application. The registers that are visible to end-user applications can all be used.
18:09:22beachebrasca: Very quickly (I am off for today). First x86-64, just because that's what I have. I hope to be able to acquire a RISC-V machine in the not-too-far future, so that would be an obvious one. I think for the other architectures, I will rely on other people to write and support backends.