These are both so weird it's best to just read the pages in full
and pay attention: [[sv/mv.swizzle]] and [[sv/mv.vec]].
Swizzle Moves only engage with vec2/3/4, *reordering* the copying
+of the sub-vector elements (including allowing repeats and skips)
based on an immediate supplied by the instruction. The fun
comes when Pack/Unpack are enabled, and it is really important
to be aware how the Arrays of vec2/3/4 become re-ordered