On Sat, 26 Apr 2025 19:11:01 GMT, fabioromano1 <d...@openjdk.org> wrote:
>> This PR optimizes `BigInteger.pow(int)` method. The primary enhancement in
>> `pow()` is not concerned most on execution time, but rather in memory
>> optimization, because the PR implementation does the "shift of the exponent"
>> squaring the result rather than the base, so the base is not squared like in
>> the current implementation, and this permits to save about half of the
>> memory.
>
> fabioromano1 has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Put power's computation in a stand-alone method
src/java.base/share/classes/java/math/BigInteger.java line 2642:
> 2640: // Use slightly different algorithms for small and large
> operands.
> 2641: // See if the result will safely fit into a long. (Largest
> 2^63-1)
> 2642: if (base.mag.length == 1 && scaleFactor <= 62) {
It seems your new `unsignedIntPow` already covers `base.mag.length == 1` case -
your `unsignedLongPow` and `unsignedIntPow` are otherwise identical. Can we
just remove this long shortcut and `unsignedLongPow` and use the newly
established `unsignedIntPow`? That can also remove lots of redundant code and
significantly reduce maintenance cost. (Unless BigInteger.multiply(long) is
much cheaper than BigInteger.multiply(BigInteger))
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/24690#discussion_r2061552026
