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Posted to dev@lucene.apache.org by "Michael McCandless (JIRA)" <ji...@apache.org> on 2014/07/29 19:02:38 UTC
[jira] [Commented] (LUCENE-5856) remove useless & 0x3f from
*BitSet.get and company
[ https://issues.apache.org/jira/browse/LUCENE-5856?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14077974#comment-14077974 ]
Michael McCandless commented on LUCENE-5856:
--------------------------------------------
+1, nice!
> remove useless & 0x3f from *BitSet.get and company
> --------------------------------------------------
>
> Key: LUCENE-5856
> URL: https://issues.apache.org/jira/browse/LUCENE-5856
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Robert Muir
> Attachments: LUCENE-5856.patch
>
>
> java specification says:
> {quote}
> If the promoted type of the left-hand operand is long, then only the six lowest-order bits of the right-hand operand are used as the shift distance. It is as if the right-hand operand were subjected to a bitwise logical AND operator & (ยง15.22.1) with the mask value 0x3f (0b111111). The shift distance actually used is therefore always in the range 0 to 63, inclusive.
> {quote}
> and x86 works the same way.
> if we remove this, we just see less instructions with printassembly...
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