gistfile1.c

int dotproduct_sse(int*F, int*S) {
    __m128i F1 = _mm_load_si128((__m128i*)F); //load aligned
    __m128i F2 = _mm_load_si128((__m128i*)F+1);
    __m128i S1 = _mm_loadu_si128((__m128i*)S); //load unaligned
    __m128i S2 = _mm_loadu_si128((__m128i*)S+1);

    __m128i res = _mm_add_epi32(_mm_mullo_epi32(F1, S1), _mm_mullo_epi32(F2, S2));

    res = _mm_add_epi32(res, _mm_srli_si128(res, 8));
    res = _mm_add_epi32(res, _mm_srli_si128(res, 4));
    return _mm_cvtsi128_si32(res);
}