Check XMM register for all zeroes

Question

Is there a way to check if all bits/bytes/words etc. in a __m128i variable are 0?
In my app I have to check if all integers packed in a in a __m128i variable are zeroes

Answer 1

_mm_testz_si128 is SSE4.1 which isn't supported on some CPUs (e.g. Intel Atom, AMD Phenom)

Here is an SSE2-compatible variant

inline bool isAllZeros(__m128i xmm) {
    return _mm_movemask_epi8(_mm_cmpeq_epi8(xmm, _mm_setzero_si128())) == 0xFFFF;
}