8285477: Add a PRECISION public static field to j.l.Float and j.l.Double #8362

rgiulietti · 2022-04-22T14:26:07Z

Add useful constants specified in IEEE 754.

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JDK-8285477: Add a PRECISION public static field to j.l.Float and j.l.Double
JDK-8285241: Add a PRECISION public static field to j.l.Float and j.l.Double (CSR)

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Joe Darcy (@jddarcy - Reviewer)

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$ git checkout pull/8362

Update a local copy of the PR:
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$ git pull https://git.openjdk.java.net/jdk pull/8362/head

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$ git pr checkout 8362

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https://git.openjdk.java.net/jdk/pull/8362.diff

bridgekeeper · 2022-04-22T14:26:51Z

👋 Welcome back rgiulietti! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

rgiulietti · 2022-04-22T14:27:06Z

The precision of float resp. double values, as defined by IEEE 754, is not easily derivable from the constants in the java.lang.Float resp. java.lang.Double classes. These values (24 resp. 53) are used in some places in the OpenJDK code base, where they appear as literals or even as derived literals, like 23 and 52. Hence, usages of these values are harder to find than necessary.

openjdk · 2022-04-22T14:29:41Z

@rgiulietti The following label will be automatically applied to this pull request:

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mlbridge · 2022-04-22T14:33:56Z

Webrevs

jddarcy · 2022-04-22T16:34:46Z

src/java.base/share/classes/java/lang/Double.java

    /**
     * Maximum exponent a finite {@code double} variable may have.
     * It is equal to the value returned by
     * {@code Math.getExponent(Double.MAX_VALUE)}.
     *
     * @since 1.6
     */
-    public static final int MAX_EXPONENT = 1023;
+    public static final int MAX_EXPONENT = (1 << (SIZE - PRECISION - 1)) - 1;


Please include the expected value as a comment; e.g.

(1 << (SIZE - PRECISION - 1)) - 1; // 1023

jddarcy · 2022-04-22T16:38:27Z

src/java.base/share/classes/java/lang/Float.java

+    /**
+     * The number of bits in the significand of a {@code float} value.
+     * This is the parameter N in section {@jls 4.2.3} of
+     * <em>The Java Language Specification</em>.


Please use "cite" rather than "em" tags for references to the JLS.

openjdk · 2022-04-25T17:04:24Z

@rgiulietti This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8285477: Add a PRECISION public static field to j.l.Float and j.l.Double

Reviewed-by: darcy

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 19 new commits pushed to the master branch:

1e79ded: 8284889: runtime/cds/appcds/loaderConstraints/DynamicLoaderConstraintsTest.java#custom-cl-zgc timed out
414918d: 8285389: EdDSA trimming zeros
293bc5e: 8129778: Few awt test fail for Solaris 11 with RuntimeException
36f2e52: 8225777: java/awt/Mixing/MixingOnDialog.java fails on Ubuntu
32593df: 8279888: Local variable independently used by multiple loops can interfere with loop optimizations
4c22a9b: 8282823: javac should constrain more uses of preview APIs
dc63584: 8273115: CountedLoopEndNode::stride_con crash in debug build with -XX:+TraceLoopOpts
c5aa75d: 8285439: remove unused os::fsync
9d9f4e5: 8285437: riscv: Fix MachNode size mismatch for MacroAssembler::verify_oops*
08024d9: 8193543: Regression automated test '/open/test/jdk/java/awt/TrayIcon/SystemTrayInstance/SystemTrayInstanceTest.java' fails
... and 9 more: https://git.openjdk.java.net/jdk/compare/165f516101016e84ebea1444fbac9b3880a940f3...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@jddarcy) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

rgiulietti · 2022-04-25T17:05:50Z

/integrate

openjdk · 2022-04-25T17:06:55Z

@rgiulietti
Your change (at version b4c1b61) is now ready to be sponsored by a Committer.

jddarcy · 2022-04-25T17:17:10Z

/sponsor

openjdk · 2022-04-25T17:18:54Z

Going to push as commit fb60594.
Since your change was applied there have been 19 commits pushed to the master branch:

1e79ded: 8284889: runtime/cds/appcds/loaderConstraints/DynamicLoaderConstraintsTest.java#custom-cl-zgc timed out
414918d: 8285389: EdDSA trimming zeros
293bc5e: 8129778: Few awt test fail for Solaris 11 with RuntimeException
36f2e52: 8225777: java/awt/Mixing/MixingOnDialog.java fails on Ubuntu
32593df: 8279888: Local variable independently used by multiple loops can interfere with loop optimizations
4c22a9b: 8282823: javac should constrain more uses of preview APIs
dc63584: 8273115: CountedLoopEndNode::stride_con crash in debug build with -XX:+TraceLoopOpts
c5aa75d: 8285439: remove unused os::fsync
9d9f4e5: 8285437: riscv: Fix MachNode size mismatch for MacroAssembler::verify_oops*
08024d9: 8193543: Regression automated test '/open/test/jdk/java/awt/TrayIcon/SystemTrayInstance/SystemTrayInstanceTest.java' fails
... and 9 more: https://git.openjdk.java.net/jdk/compare/165f516101016e84ebea1444fbac9b3880a940f3...master

Your commit was automatically rebased without conflicts.

openjdk · 2022-04-25T17:19:10Z

@jddarcy @rgiulietti Pushed as commit fb60594.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

8285477: Add a PRECISION public static field to j.l.Float and j.l.Double

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openjdk bot added csr Pull request needs approved CSR before integration rfr Pull request is ready for review labels Apr 22, 2022

openjdk bot added the core-libs core-libs-dev@openjdk.org label Apr 22, 2022

8285477: Add a PRECISION public static field to j.l.Float and j.l.Double

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jddarcy reviewed Apr 22, 2022

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8285477: Add a PRECISION public static field to j.l.Float and j.l.Double

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jddarcy approved these changes Apr 22, 2022

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openjdk bot removed the csr Pull request needs approved CSR before integration label Apr 25, 2022

openjdk bot added the ready Pull request is ready to be integrated label Apr 25, 2022

openjdk bot added the sponsor Pull request is ready to be sponsored label Apr 25, 2022

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openjdk bot closed this Apr 25, 2022

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review sponsor Pull request is ready to be sponsored labels Apr 25, 2022

rgiulietti deleted the JDK-8285477 branch April 26, 2022 12:06

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8285477: Add a PRECISION public static field to j.l.Float and j.l.Double #8362

8285477: Add a PRECISION public static field to j.l.Float and j.l.Double #8362

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8285477: Add a PRECISION public static field to j.l.Float and j.l.Double #8362

8285477: Add a PRECISION public static field to j.l.Float and j.l.Double #8362

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