code: public BigInteger toBigInteger() {
          byte[] magnitude = new byte[nWords * 4 + 1];
          for (int i = 0; i < nWords; i++) {
              int w = data[i];
              magnitude[magnitude.length - 4 * i - 1] = (byte) w;
              magnitude[magnitude.length - 4 * i - 2] = (byte) (w >> 8);
              magnitude[magnitude.length - 4 * i - 3] = (byte) (w >> 16);
              magnitude[magnitude.length - 4 * i - 4] = (byte) (w >> 24);
          }
          return new BigInteger(magnitude).shiftLeft(offset * 32);
      }
docs: Converts this <code>FDBigInteger</code> to a <code>BigInteger</code>.
  
  @return The <code>BigInteger</code> representation.