It makes sense if you're counting register _encodings_ (that is, how much ISA encoding space the registers use). But yeah, a more useful count would consider th

It makes sense if you're counting register _encodings_ (that is, how much ISA encoding space the registers use). But yeah, a more useful count would consider the sub-registers as part of the main register (and the same for other ISAs like 64-bit ARM, which does have a 32-bit view of its 64-bit general purpose registers), and would not consider registers outside each core (like the MTRR registers).