227 lines
8.1 KiB
HTML
227 lines
8.1 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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"http://www.w3.org/TR/html4/strict.dtd">
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<!-- Material used from: HTML 4.01 specs: http://www.w3.org/TR/html401/ -->
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<html>
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<head>
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<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>OpenMP* : Support for the OpenMP language</title>
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<link type="text/css" rel="stylesheet" href="menu.css">
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<link type="text/css" rel="stylesheet" href="content.css">
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</head>
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<body>
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<div id="menu">
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<div>
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<a href="http://llvm.org/">LLVM Home</a>
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</div>
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<div class="submenu">
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<label>OpenMP Info</label>
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<a href="/index.html">About</a>
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</div>
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<div class="submenu">
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<label>Quick Links</label>
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<a href="http://lists.llvm.org/mailman/listinfo/openmp-dev">openmp-dev</a>
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<a href="http://lists.llvm.org/mailman/listinfo/openmp-commits">openmp-commits</a>
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<a href="http://llvm.org/bugs/">Bug Reports</a>
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<a href="https://github.com/llvm/llvm-project/tree/master/openmp">Browse Sources</a>
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</div>
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</div>
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<div id="content">
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<!--*********************************************************************-->
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<h1>OpenMP®: Support for the OpenMP language</h1>
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<!--*********************************************************************-->
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<p>The OpenMP subproject of LLVM contains the
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components required to build an executable OpenMP program that are
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outside the compiler itself.
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</p>
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<p>Here you can find :-
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<ul>
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<li>
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the code for the runtime library against which
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code compiled by <tt>clang -fopenmp</tt> must be linked before it
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can run.
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</li>
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<li>
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the library that supports offload to target devices (in
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"libomptarget")
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</li>
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</ul>
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</p>
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<p>Support for the parts of the OpenMP 4.0 (and later) language that are not
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associated with the "target" constructs are contained in the
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"runtime" directory. Support for offloading computation via the
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"target" directive is in the separate "libomptarget" directory.
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</p>
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<p>All of the code here is <a
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href="http://llvm.org/docs/DeveloperPolicy.html#license">dual licensed</a>
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under the MIT license and the UIUC License (a BSD-like license).
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The LICENSE.txt file at the top of the OpenMP project contains
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the license text and associated patent grants.
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</p>
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<!--=====================================================================-->
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<h2 id="dir-structure">Status</h2>
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<!--=====================================================================-->
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<p>With the release of Clang 3.8.0, OpenMP 3.1 support is enabled in
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Clang by default, and the OpenMP runtime is therefore built as a
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normal part of the Clang build, and distributed with the binary
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distributions.You do not, therefore, need explicitly to check out this code, or
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build it out of tree; a normal Clang check out and build will
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automatically include building these runtime libraries.
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</p>
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<!--=====================================================================-->
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<h2 id="goals">Features and Goals</h2>
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<!--=====================================================================-->
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<ul>
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<li>Support for the <a href="http://www.openmp.org/mp-documents/OpenMP3.1.pdf">OpenMP
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3.1 standard (PDF)</a> has been achieved in the Clang 3.8.0
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release.
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</li>
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<li>Support for the
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<a href="http://www.openmp.org/mp-documents/OpenMP4.0.0.pdf">OpenMP
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4.0 standard (PDF)</a> and <a href="http://www.openmp.org/mp-documents/OpenMP4.5.pdf">OpenMP
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4.5 standard (PDF)</a> is now being implemented. (Some OpenMP 4.0
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and 4.5 features are already available).
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<li>High performance.</li>
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<li>ABI compatibility with <a href="http://gcc.gnu.org">Gcc</a> and
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<a href="http://software.intel.com/en-us/intel-compilers">Intel's
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existing OpenMP compilers.</a>
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We currently have binary compatibility with OpenMP
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3.1 code compiled by gcc 4.9, however we do not have support
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for OpenMP 4.0 code that uses task cancellation when compiled
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by gcc 4.9. How we will support such code remains a research issue.
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</li>
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</ul>
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<!--=====================================================================-->
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<h2 id="why">Why have the runtime code here?</h2>
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<!--=====================================================================-->
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<p>It makes sense to have the runtime sources in the same place
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(and with the same license) as the compiler.
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</p>
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<!--=====================================================================-->
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<h2 id="requirements">Platform Support</h2>
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<!--=====================================================================-->
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<p>The runtime can be built with gcc, icc or clang. However, note
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that a runtime built with clang cannot be guaranteed to work with
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OpenMP code compiled by the other compilers, since clang does not support
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a 128-bit float type, and cannot therefore generate the code used
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for reductions of that type (which may occur in user code compiled
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by the other compilers).
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</p>
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<p>The OpenMP runtime is known to work on
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<ul>
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<li>ARM® architecture processors</li>
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<li>PowerPC™ processors</li>
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<li>32 and 64 bit X86
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processors when compiled with clang, with the Intel compiler
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or with gcc, and also the Intel® Xeon Phi™ product family, when compiled with
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the Intel compiler.
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</li>
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<li>MIPS and MIPS64</li>
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</ul>
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Ports to other architectures and operating systems are welcome.
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</p>
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<p>A full OS and architecture compatibility matrix is in
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<a href="README.txt">README.txt</a>
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</p>
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<!--=====================================================================-->
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<h2>Get it and get involved!</h2>
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<!--=====================================================================-->
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<p>First please review our
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<a href="http://llvm.org/docs/DeveloperPolicy.html">Developer's Policy</a>.
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<p>To check out the code, use:</p>
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<ul>
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<li><code>git clone https://github.com/llvm/llvm-project.git</code></li>
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</ul>
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<p>In-tree build:</p>
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<ul>
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<li><code>cd llvm-project</code></li>
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<li><code>mkdir build && cd build</code></li>
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<li><code>cmake ../llvm -DLLVM_ENABLE_PROJECTS=openmp -DCMAKE_C_COMPILER=<C compiler> -DCMAKE_CXX_COMPILER=<C++ compiler></code></li>
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<li><code>make omp</code></li>
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</ul>
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<p>Out-of-tree build:</p>
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<ul>
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<li><code>cd llvm-project</code></li>
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<li><code>mkdir build-openmp && cd build-openmp</code></li>
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<li><code>cmake ../openmp -DCMAKE_C_COMPILER=<C compiler> -DCMAKE_CXX_COMPILER=<C++ compiler></code></li>
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<li><code>make</code></li>
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</ul>
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<p>Full details of how to build are in the
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<a href="README.txt">README.txt</a> and README.rst in the source code repository.
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</p>
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<!--=====================================================================-->
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<h3>Notes</h3>
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<!--=====================================================================-->
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<p>
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</p>
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<p>Send discussions to the
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(<a href="http://lists.llvm.org/mailman/listinfo/openmp-dev">OpenMP mailing list</a>).</p>
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<!--=====================================================================-->
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<h2>Design Documents</h2>
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<!--=====================================================================-->
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<ul>
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<li><a href="Reference.pdf">Runtime design (PDF)</a></li>
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</ul>
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<!--=====================================================================-->
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<h2>Copyright notices</h2>
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<!--=====================================================================-->
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<ul>
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<li>
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The OpenMP name and the OpenMP logo are registered trademarks of the
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OpenMP Architecture Review Board.
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</li>
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<li>
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Intel is a trademark of Intel Corporation in the U.S. and/or other
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countries.
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</li>
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<li>
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PowerPC is a trademark of IBM Corporation in the U.S. and/or other
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countries.
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</li>
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<li>
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ARM is a trademark of ARM Corporation in the U.S. and/or
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other countries.
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</li>
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<li>
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MIPS is a trademark of MIPS Computer Systems in the U.S. and/or
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other countries.
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</li>
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</ul>
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</div>
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</body>
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</html>
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