*     is not precisely representable as a {@code double}
   * @since 30.0
   */
  public static double roundToDouble(BigDecimal x, RoundingMode mode) {
    return BigDecimalToDoubleRounder.INSTANCE.roundToDouble(x, mode);
  }

  private static final class BigDecimalToDoubleRounder extends ToDoubleRounder<BigDecimal> {

      tmp += BigIntegerMath.divide(nonzero1[j], nonzero2[j], mode).intValue();
    }
    return tmp;
  }

  @Benchmark
  long roundToDouble(int reps) {
    long tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;
      tmp += Double.doubleToRawLongBits(BigIntegerMath.roundToDouble(nonzero1[j], mode));
    }
    return tmp;
  }

      tmp += BigIntegerMath.divide(nonzero1[j], nonzero2[j], mode).intValue();
    }
    return tmp;
  }

  @Benchmark
  long roundToDouble(int reps) {
    long tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;
      tmp += Double.doubleToRawLongBits(BigIntegerMath.roundToDouble(nonzero1[j], mode));
    }
    return tmp;
  }

  abstract X toX(double d, RoundingMode mode);

  /** Returns a - b, guaranteed that both arguments are nonnegative. */
  abstract X minus(X a, X b);

  /** Rounds {@code x} to a {@code double}. */
  final double roundToDouble(X x, RoundingMode mode) {
    checkNotNull(x, "x");
    checkNotNull(mode, "mode");
    double roundArbitrarily = roundToDoubleArbitrarily(x);
    if (Double.isInfinite(roundArbitrarily)) {
      switch (mode) {