static void keccak_absorb4x()

in src/sha3/fips202x4.c [37:97]

• 55 lines of code
• 6 McCabe index (conditional complexity)

static void keccak_absorb4x(__m256i *s, unsigned int r, const unsigned char *m0, const unsigned char *m1, const unsigned char *m2, const unsigned char *m3, 
                            unsigned long long int mlen, unsigned char p)
{
  unsigned long long i;
  unsigned char t0[200];
  unsigned char t1[200];
  unsigned char t2[200];
  unsigned char t3[200];
  unsigned long long *ss = (unsigned long long *)s;
   
  while (mlen >= r) 
  {
    for (i = 0; i < r / 8; ++i)
    {
      ss[4*i+0] ^= load64(m0 + 8 * i);
      ss[4*i+1] ^= load64(m1 + 8 * i);
      ss[4*i+2] ^= load64(m2 + 8 * i);
      ss[4*i+3] ^= load64(m3 + 8 * i);
    }
    
    KeccakF1600_StatePermute4x(s);
    mlen -= r;
    m0 += r;
    m1 += r;
    m2 += r;
    m3 += r;
  }

  for (i = 0; i < r; ++i)
  {
    t0[i] = 0;
    t1[i] = 0;
    t2[i] = 0;
    t3[i] = 0;
  }
  for (i = 0; i < mlen; ++i)
  {
    t0[i] = m0[i];
    t1[i] = m1[i];
    t2[i] = m2[i];
    t3[i] = m3[i];
  }

  t0[i] = p;
  t1[i] = p;
  t2[i] = p;
  t3[i] = p;

  t0[r - 1] |= 128;
  t1[r - 1] |= 128;
  t2[r - 1] |= 128;
  t3[r - 1] |= 128;

  for (i = 0; i < r / 8; ++i)
  {
    ss[4*i+0] ^= load64(t0 + 8 * i);
    ss[4*i+1] ^= load64(t1 + 8 * i);
    ss[4*i+2] ^= load64(t2 + 8 * i);
    ss[4*i+3] ^= load64(t3 + 8 * i);
  }
}