Comment by rapidlua

Thank you for the feedback! A new calling convention could probably nail it for many use cases. Sometimes you want something very special though. E.g. LuaJIT pre-decodes instruction prior to dispatch to squeeze some work into branch misprediction delay. There are limited callee save registers available hence it is better to use volatile registers for instruction arguments. It should be possible to reuse the implementation on different architectures and only tweak the register assignment.