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  1. JDK
  2. JDK-4141677

The spec for java.lang.Math should not be written in C.

    Details

    • Type: Bug
    • Status: Open
    • Priority: P4
    • Resolution: Unresolved
    • Affects Version/s: 1.1.6, 1.4.1
    • Fix Version/s: tbd_major
    • Component/s: core-libs
    • Labels:
    • Subcomponent:
    • Understanding:
      Cause Known
    • CPU:
      x86, sparc
    • OS:
      linux, solaris_2.5

      Description

      Name: mgC56079 Date: 05/26/98



      The licensee has a problem with java.lang.Math.pow function.
      The behaviour of pow in their system is different from reference implementation.
      However, there is no clear spec for mathematical functions.
      The JLS refers to C implementation of fdlibm as a spec.
      This is not a good thing. We cannot rely on C behaviour in the JLS.
      A possible solution is to provide reference implementation of java.lang.Math in java.

      > Date: Thu, 21 May 1998 18:22:50 +0900
      > From: Shigeru Santo <###@###.###>
      > To: ###@###.###
      > Subject: The certification process
      > Product Name: Developer's Kit for Java
      > Platform: HI-UX/WE2 (Hitachi's unix platform)
      > Based on: JDK 1.1.6 Solaris reference
      >
      > The certification process:
      > We have run all of the test in the JCK 1.1.6a, and get the following
      > failed items. All other items have been passed.
      >
      > I believe all of these failed items are allowable to get the Java logo.
      > So, I would like you to give us a right to contact with JavaSoft
      > Marketing Communications to request the logo artwork.
      >
      > The explanations for the each failed items:
      >
      > *** Case (1) to (4): The result from our pow() library is slightly
      > different from the result in the Solaris, and all these test cases are
      > expecting exactly the same return value as the Solaris's pow().
      >
      > For example:
      > pow(2.0, -51.0)
      > 0x3CBFFFFFFFFFFFED^[$B!!!!!!!!!!^[(JHI-UX/WE2
      > 0x3CC0000000000000^[$B!!!!!!!!!!^[(JSolaris
      >
      > I believe this is allowable difference.
      >
      > I think you should not expect exactly the same return value as your
      > math library that is treating the floating point value.
      > The result of such a library must be checked by a range,
      > e.g. low < result < high.
      >
      > Because the result would be slightly differs by the algorithm that is
      > chosen by the library, and JLS does not define the algorithm of the
      > library.
      >
      > =================== The results ==================================
      >
      > -------------------- pow() problem -----------------------------
      >
      > (1)/java -verify
      > javasoft.sqe.tests.vm.classfmt.cpl.cpldbl005.cpldbl00501
      > ----------ref:testExecute(1/14)----------
      > invalid value
      > ----------log:testExecute(0/0)----------
      >
      >
      > (2)/java -verify
      > javasoft.sqe.tests.vm.classfmt.cpl.cplflt005.cplflt00501
      > ----------ref:testExecute(1/14)----------
      > invalid value
      > ----------log:testExecute(0/0)----------
      >
      > (3)/java -verify
      > javasoft.sqe.tests.api.java.lang.Float.intBitsToFloat25Tests
      > ----------ref:testExecute(56/2917)----------
      >
      > STATUS:Failed.tests: 16; passed: 10; failed: 6; first test case failure:
      > 0:1
      > command result: Failed. tests: 16; passed: 10; failed: 6; first test
      > case failure: 0:1
      > test result: Failed. tests: 16; passed: 10; failed: 6; first test case
      > failure: 0:1
      >
      > (4)/java -verify
      > javasoft.sqe.tests.api.java.lang.Double.longBitsToDouble4Tests
      > ----------ref:testExecute(42/2235)----------
      >
      > STATUS:Failed.tests: 13; passed: 9; failed: 4; first test case failure:
      > 0:1
      > command result: Failed. tests: 13; passed: 9; failed: 4; first test case
      > failure: 0:1
      > test result: Failed. tests: 13; passed: 9; failed: 4; first test case
      > failure: 0:1

      ======================================================================
      ###@###.### 2004-11-11 21:46:39 GMT

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              • Assignee:
                darcy Joe Darcy
                Reporter:
                mgorshen Mikhail Gorshenev (Inactive)
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