Function vcopyq_lane_u64

pub unsafe fn vcopyq_lane_u64(
    a: uint64x2_t,
    const LANE1: i32,
    b: uint64x1_t,
    const LANE2: i32,
) -> uint64x2_t

Available on (AArch64 or target_arch="arm64ec") and target feature neon only.

Insert vector element from another vector element

Arm’s documentation