Addition with Morton interleaved coordinates

Morton3Add.cpp

const uint64_t x3_mask = 0x9249249249249249; // 0b...01001001
const uint64_t y3_mask = 0x2492492492492492; // 0b...10010010
const uint64_t z3_mask = 0x4924924924924924; // 0b...00100100
const uint64_t xy3_mask = x3_mask | y3_mask;
const uint64_t xz3_mask = x3_mask | z3_mask;
const uint64_t yz3_mask = y3_mask | z3_mask;

const uint64_t x2_mask = 0x55555555; //0b...01010101
const uint64_t y2_mask = 0xAAAAAAAA; //0b...10101010

/* Add two morton keys (xy interleaving) */
uint64_t Morton2Add(uint64_t m1, uint64_t m2)
{
  uint64_t x_sum = ( m1 | y2_mask) + (m2 & x2_mask);
  uint64_t y_sum = ( m1 | x2_mask) + (m2 & y2_mask);
  return (x_sum & x2_mask) | (y_sum & y2_mask);
}

/* Add two morton keys (xyz interleaving) */
uint64_t Morton3Add(uint64_t m1, uint64_t m2)
{
  uint64_t x_sum = ( m1 | yz3_mask) + (m2 & x3_mask);
  uint64_t y_sum = ( m1 | xz3_mask) + (m2 & y3_mask);
  uint64_t z_sum = ( m1 | xy3_mask) + (m2 & z3_mask);
  return (x_sum & x3_mask ) | (y_sum & y3_mask ) | (z_sum & z3_mask);
}