dest[i] = src[swiz[i]]
-Note that 7 options are needed (not 6) because option 0b000 allows static
+Note that 8 options are needed (not 6) because option 0b001 encodes
+the subvector length, and option 0b000 allows static
predicate masking (skipping) to be encoded within the swizzle immediate.
For example it allows "W.Y." to specify: "copy W to position X,
and Y to position Z, leave the other two positions Y and W unaltered"