RFR: 8339934: Simplify Math.scalb(double) method [v2]

[Joe Darcy]

On Fri, 13 Sep 2024 08:56:39 GMT, Raffaello Giulietti <rgiulietti at openjdk.org> wrote:

>> `Math.scalb(double)` can be simplified, removing a loop and using larger/smaller factors.
>
> Raffaello Giulietti has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Slight improvement.

src/java.base/share/classes/java/lang/Math.java line 3325:

> 3323:         if (scaleFactor > -DoubleConsts.EXP_BIAS) {
> 3324:             if (scaleFactor <= DoubleConsts.EXP_BIAS) {
> 3325:                 return d * longBitsToDouble((long) (scaleFactor + DoubleConsts.EXP_BIAS) << PRECISION - 1);

The longBitsToDouble call is basically an inline form of powerOfTwoD. I'd prefer to see that method used for clearer semantics. Optimization of  powerOfTwoD would be fine.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20948#discussion_r1759320117