#8014320 would benefit from #5100935

Joe Darcy joe.darcy at oracle.com
Sun Mar 23 18:09:44 UTC 2014


The description of 5100935 is:

     JDK-5100935 No way to access the 64-bit integer multiplication of 
64-bit CPUs efficiently

 From the most recent comment in the bug, the straw-man API for this is 
something like:

> For the (int, int) -> long case, "multiplyFull".
> For the high bits of (long, long) -> long, "multiplyHigh

with expected VM intrinsification.

FWIW, I'd like to see this API included in JDK 9.


On 3/23/2014 3:06 AM, Tim Buktu wrote:
> Posting to the list because I can't add comments on
> http://bugs.openjdk.java.net.
> I just wanted to point out that if #5100935 were implemented, it would
> allow for a speed improvement of an estimated 20% for SS multiplication
> in the 20,000 - 80,000 digit range.
> There are other improvements to 8014320 that could be done now, but they
> would only make a difference well into the 100,000s of digits.
> Tim

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