Function write_element_0_u64 

pub unsafe fn write_element_0_u64<const VLEN: Vlen>(
    vregs: &mut VectorRegisterFile<VLEN>,
    base_reg: VReg,
    sew: Vsew,
    value: u64,
)

Write element 0 of register base_reg from the low sew_bytes of value.

Safety

sew.bytes() <= VLEN.bytes()