(dest r# is scalar) -> VSELECT mode
imm(RA) RT.v RA.s fixed stride: unit or element
sv.ld r#.v, ofst(r#2).v -> whole vector is at ofst+r#2
- mem@r# +0 +1 +2
+ mem@r#2 +0 +1 +2
destreg r# r#+1 r#+2
sv.ld/els r#.v, ofst(r#2).v -> vector at ofst*elidx+r#2
- mem@r# +0 ... +offs ... +offs*2
+ mem@r#2 +0 ... +offs ... +offs*2
destreg r# r#+1 r#+2
imm(RA) RT.s RA.s not vectorised
sv.ld r#, ofst(r#2)