Unless otherwise stated, reserved values are always all zeros.
This is unlike OpenPower ISA v3.1, which in many instances does not
-require a trap if reserved fields are nonzero. Where the standard Power
+require a trap if reserved fields are nonzero, instead relying on software
+to avoid use of such fields. Where the standard Power
ISA definition is intended the red keyword `RESERVED` is used.
## Definition of "UnVectoriseable"