pqc_kyber 0.2.1

A rust implementation of the post-quantum Kyber KEM algorithm
Documentation 
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use core::arch::x86_64::*;

pub fn verify(a: &[u8], b: &[u8], mut len: usize) -> u8
{
  let (mut f, mut g);
  let mut r: u64;
  unsafe {
    let mut h =  _mm256_setzero_si256();
    for i in 0..(len/32) {
      f = _mm256_loadu_si256(a[32*i..].as_ptr() as *const __m256i);
      g = _mm256_loadu_si256(b[32*i..].as_ptr() as *const __m256i);
      f = _mm256_xor_si256(f,g);
      h = _mm256_or_si256(h,f);
    }
    r = 1 -  _mm256_testz_si256(h,h) as u64;
  }
  let idx = 32*(len/32);
  len -= idx;
  for i in 0..len {
    r |= (a[idx+i] ^ b[idx+i]) as u64;
  }
  (r.wrapping_neg() >> 63) as u8
}

pub fn cmov(r: &mut[u8], x: &[u8], mut len: usize, mut b: u8)
{
  let (mut xvec, mut rvec);
  unsafe {
    let bvec = _mm256_set1_epi64x(b as i64);
    for i in 0..(len/32) {
      rvec = _mm256_loadu_si256(r[32*i..].as_ptr() as *const __m256i);
      xvec = _mm256_loadu_si256(x[32*i..].as_ptr() as *const __m256i);
      rvec = _mm256_blendv_epi8(rvec,xvec,bvec);
      _mm256_storeu_si256(r[32*i..].as_mut_ptr() as *mut __m256i,rvec);
    }
  }
  let idx = 32*(len/32);
  len -= idx;
  b = b.wrapping_neg();
  for i in 0..len {
    r[idx+i] ^= b & (x[idx+i] ^ r[idx+i]);
  }
}