docs: static DiyFp asNormalizedDiyFp(long d64) {
          long f = significand(d64);
          int e = exponent(d64);
  
          assert(f != 0);
  
          // The current double could be a denormal.
          while ((f & kHiddenBit) == 0) {
              f <<= 1;
              e--;
          }
          // Do the final shifts in one go. Don't forget the hidden bit (the '-1').
          f <<= DiyFp.kSignificandSize - kSignificandSize - 1;
          e -= DiyFp.kSignificandSize - kSignificandSize - 1;
          return new DiyFp(f, e);
      }