On Wed, 7 May 2025 17:51:05 GMT, fabioromano1 <d...@openjdk.org> wrote:
>> At some point you proposed >> >> (bitLength() - 1L) * exponent >= (long) MAX_MAG_LENGTH << 5 >> >> Given the value of `MAX_MAG_LENGTH`, which is 2^26, this is equivalent to >> >> (bitLength() - 1L) * exponent >= 1L << 31 >> >> that is, to >> >> (bitLength() - 1L) * exponent > Integer.MAX_VALUE >> >> >> What am I missing? > > The condition `A := (bitLength() - 1L) * exponent + 1L > Integer.MAX_VALUE` > is more accurate, as it compares the bit length of the result, in fact `B := > (bitLength() - 1L) * exponent >= (long) MAX_MAG_LENGTH << 5` implies `A`, but > `A` does not imply `B`. The `BigInteger`s can have a mag length up to > `MAX_MAG_LENGTH`, but `MAX_MAG_LENGTH * Integer.SIZE > Integer.MAX_VALUE`. OK. But then your original expression (((bitLength() - 1L) * exponent) >>> 5) + 1L > MAX_MAG_LENGTH was a bit too restrictive as well, right? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/24690#discussion_r2078191934
