Thanks! This and some of the other comments have been helpful in understanding how these things work in more detail. So conceptually register names should be se

Thanks! This and some of the other comments have been helpful in understanding how these things work in more detail. So conceptually register names should be seen as result names - the result of a load or an operation gets called r2 for example. The ISA only provides so many result names, but the CPU may have any number of physical registers to store results. It's a nice model, and modifying a result in-register would really mess things up. It would destroy a previous result which would require a very different (more complex) approach to scheduling and clean up.