func: static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
  
  {
  
      long i;
  
      for (i = 0; i <= w - sizeof(long); i += sizeof(long)) {
  
          long a = *(long *)(src1 + i);
  
          long b = *(long *)(src2 + i);
  
          *(long *)(dst + i) = ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80);
  
      }
  
      for (; i < w; i++)
  
          dst[i] = src1[i] + src2[i];
  
  }
  