* A third 24-bits (third 2-bit XO) is strongly recommended to be `RESERVED`
such that future unforeseen capability is needed (although this may be
alternatively achieved with a mandatory PCR or MSR bit)
-* To hold all Vector Context, five SPRs are needed for userspace.
- If Supervisor and Hypervisor mode are to
- also support Simple-V they will correspondingly need five SPRs each.
+* To hold all Vector Context, four SPRs are needed.
(Some 32/32-to-64 aliases are advantageous but not critical).
* Five 6-bit XO (A-Form) "Management" instructions are needed. These are
Scalar 32-bit instructions and *may* be 64-bit-extended in future
Context-switching and no adverse latency, it may be considered to
be a "Sub-PC" and as such absolutely must be treated with the same
respect and priority as MSR and PC.
-* **SVSRR0** - identical in purpose to SRR0/1: storing SVSTATE on context-switch
- along-side MSR and PC.
* **SVSHAPE0-3** - these are 32-bit and may be grouped in pairs, they REMAP
(shape) the Vectors[^svshape]
* **SVLR** - again similar to LR for exactly the same purpose, SVSTATE