+# Definitions
+
+**Proposal: Add the following Definition to Section 1.3.1 of Book I**
+
+Definition of "UnVectoriseable":
+
+Any operation that inherently makes no sense if repeated (through SVP64
+Prefixing) is termed "UnVectoriseable" or "UnVectorised". Examples
+include `sc` or `sync` which have no registers. `mtmsr` is also classed
+as UnVectoriseable because there is only one `MSR`.
+
+UnVectorised instructions are required to be detected as such if
+Prefixed (either SVP64 or SVP64Single) and an Illegal Instruction
+Trap raised.
+
+*Architectural Note: Given that a "pre-classification" Decode Phase is
+required (identifying whether the Suffix - Defined Word - is
+Arithmetic/Logical, CR-op, Load/Store or Branch-Conditional),
+adding "UnVectorised" to this phase is not unreasonable.*
+
# New 64-bit Instruction Encoding spaces
+**Proposal: Add new Section 1.6.5 to Book I**
+
The following seven new areas are defined within Primary Opcode 9 (EXT009)
as a new 64-bit encoding space, alongside Primary Opcode 1
(EXT1xx).
they may equally be allocated entirely differently.
*Architectural Resource Allocation Note: **under no circumstances** must
-different Defined Words be allocated within any `EXT{z}` prefixed
-or unprefixed space for a given value of `z`. Even if UnVectoriseable
+different Defined Words be allocated within any `EXT{z}` prefixed or
+unprefixed space for a given value of `z` of 0, 2 or 3. Even if UnVectoriseable
an instruction Defined Word space must have the exact same Instruction
-and exact same Instruction Encoding in all spaces being RESERVED - Illegal
-Instruction Trap - if UnVectoriseable) or not be allocated at all.
+and exact same Instruction Encoding in all spaces being RESERVED (Illegal
+Instruction Trap if UnVectoriseable) or not be allocated at all.
This is required as an inviolate hard rule governing Primary Opcode 9
that may not be revoked under any circumstances. A useful way to think
of this is that the Prefix Encoding is, like the 8086 REP instruction,