Function _mm_insert_si64
#[target_feature(enable = "sse4a")]
pub fn _mm_insert_si64(x: __m128i, y: __m128i) -> __m128iInserts the [length:0] bits of y into x at index.
The bits of y:
[69:64]specify thelength,[77:72]specify the index.
If the length is zero it is interpreted as 64. If index + length > 64
or index > 0 && length == 0 the result is undefined.
The upper 64 bits of the destination are undefined.