prime

#include <vector>
#include <immintrin.h>

int main() {
    std::vector<__m256i> primes = { _mm256_setr_epi32(2, ~0, ~0, ~0, ~0, ~0, ~0, ~0) };
    primes.reserve(2048);

    unsigned sqr = 4;
    int pos = 1;

    for (unsigned current = 3; current < uint32_t(1e2); current += 2) {
        auto num = _mm256_set1_epi32(current);
        if (sqr * sqr < current) {
            ++sqr;
        }
        for (auto divisor : primes) {
            auto temp = _mm256_cmpeq_epi32(
                _mm256_rem_epu32(num, divisor),
                _mm256_setzero_si256()
            );
            if (!_mm256_testz_si256(temp, temp)) {
                break; // not prime
            }
            if (unsigned(_mm256_extract_epi32(divisor, 7)) > sqr) {
                // prime number found

                reinterpret_cast<uint32_t *>(&primes.back())[pos] = current;
                if (++pos >= 8) {
                    primes.push_back(_mm256_set1_epi32(~0));
                    pos = 0;
                }
                break;
            }
        }
    }
}