Hello,
By browsing the Register Addendum, I infer the following pattern:
CR5A0 -> R5SS0 CORE0
CR5A1 -> R5SS1 CORE0
CR5B0 -> R5SS0 CORE1
CR5B1 -> R5SS1 CORE1
In other words:
A/B = Core 0 or 1 respectively.
0/1 = Subsystem 0 or 1 respectively.
Have I understood that correctly please?