This is interesting. While I agree that CPUs no longer have the set of registers used the way they were on the Honeywell, they certainly do have special groups

This is interesting. While I agree that CPUs no longer have the set of registers used the way they were on the Honeywell, they certainly do have special groups of registers that can only be used for some operations and not others. For example, FPU registers don't generally do logical operations. SIMD registers either don't work as general purpose registers, or have to be switched from being general purpose to being SIMD depending on the architecture. So there are still "special register groups" on modern CPUs. It just doesn't mean the same thing as it meant back then. Kind of funny.