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<h1><a name="socgen_project"></a>SOCGEN Project</h1>
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<h1><a name="socgen_project"></a><font size="+3">SOCGEN Project</font></h1>
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<h2><a name="manifesto"></a>Database Guidelines</h2>
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<h2><br>
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</h2>
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The mission of the SOCGEN project is to provide a blueprint showing
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digital designers how to create a System_on_chip (SOC) by
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assembling components created by a variety of sources. It will
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show how to create a component that can be reused and provides a
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free opensourced tool set that can be used to assemble and verify
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a design. It employs modern design for reuse techniques to reduce the
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waste and ineffiencies that is inherent in handcrafting a design<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<br>
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<h2><a name="manifesto"></a><font size="+2">Principles for Reusable
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design</font><br>
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</h2>
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<p><br>
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<p><br>
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</p>
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<p>Have a backup plan</p>
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<p> <br>
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<br>
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<br>
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<h2><font size="+1">Plan ahead<br>
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</font></h2>
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You may start a design with the intent that it is only going to be used
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for one specific purpose only to find out later that other designers
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want to use it. Create all designs with the intent that they will be
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reused in ways that you haven't imagined and you won't have to scramble
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later. <br>
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<br>
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<h2><font><font size="+1">Design for the lowest common demoninator</font></font></h2>
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Everybody loves to use some quirky little feature of the design target
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to squeeze a little extra preformance out of the system. But if you do
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then you are locked into that target and cannot easily reuse the design
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on a different target. Why do you think they put those features in the
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first place? Instead you should survey the field and only use the
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features that all target technologies can match<br>
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<br>
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<br>
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<h2><font><font><font><font size="+1">Design in a completely generic
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technology<br>
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</font></font></font></font></h2>
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Design is a two step process. First the design is created and verified
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in a completely generic behaverioral RTL format and then converted into
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the target technology. It is tempting to try to save time be designing
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in the target technology but this will make it harder to reuse.<br>
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<br>
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<br>
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<h2><font><font><font><font><font><font><font><font size="+1">Automate
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Everything</font></font></font></font></font></font></font></font><br>
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</h2>
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<p>
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Handcrafting a design file is a time consuming and error prone
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operation. Tasks that are preformed on every design should be done by a
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tool. The designers job is to create the configuration files
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needed by the tools and let automation do all the work.<br>
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</p>
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</p>
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<p>Plan ahead and allow for the worst case configurations</p>
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<p>Design for the lowest common denominator.</p>
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<p>Design first for a completely generic target and then retarget for
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the correct one.</p>
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<p>Store only the seed data needed to generate the database ( keep it
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small and easy to manage)</p>
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<p>Do not check generated files into the database ( generation must
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not change the database)</p>
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<p>Do not copy data. Every object has one and one one storage
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location</p>
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<p>Do not mix unlike objects in the same container. </p>
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<p>Store the databases by their source and not by where they are
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used. Use links to get them to where they are needed</p>
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<p>A full design will consist of several different databases that are
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layered. Upper ones may override any content from a lower layer</p>
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<p><br>
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<p><br>
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</p>
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<h2><font><font><font><font><font><font><font><font size="+1">Never
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Check Generated Files into a Database</font></font></font></font></font></font></font></font></h2>
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The Revision Control System (RCS) that contains the design should only
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contain the minimul seed data needed to rebuild the entire design. It
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should never contain any files that were generated by the build
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process. <br>
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<br>
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<h2><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font
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size="+1">Do not keep duplicate copies of a file in the database</font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></h2>
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Doing so makes it difficult to ensure that bug fixes and enhancements
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created by one user can be made available to all users. Every file
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should have one and only one location in the database<br>
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<br>
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<br>
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<h2><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font
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size="+1">Do not build the design inside of an RCS database.</font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></h2>
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It is really hard to keep track of all the new files that you have
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added that you need to check into the RCS if they are buried by
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gigabytes of generated files from the build process. Use symbolic links
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to create a work area where generated files are kept outside the
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database.<br>
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<br>
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<p>
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</p>
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<p></p>
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<h2><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font
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size="+1">Store files based on their source and not their use.</font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></h2>
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Are you creating a chip using IP from Joe's IP Emporium? Why not create
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a spot inside your chip database for Joes files? Because that is not
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planning ahead. Later if your lab starts another chip that also uses
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Joes IP then they will also need access to those files. Create a spot
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for files where everybody can simply access them by linking the desired
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files into there database<font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font
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size="+1">.</font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font>
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<p></p>
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<h2><br>
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</h2>
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<h2><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font
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size="+1">Do not mix unlike objects in the same container.</font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></h2>
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<p>"Unlike" is a delibertely nebulious term. It can mean anything and
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everything. If you have a instance of a hard macro that is
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unsynthesizable then do not put it in a file along with synthesisable
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rtl code. If you have code belonging to one designer then do not mix it
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with code belonging to another. If you do then you have to worry about
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file locking. Fragment the design so that each object is in it's own
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container and then use a tool to put them back together.<br>
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</p>
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<br>
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<br>
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<h2><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font><font>Layer
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the
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design.</font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></font></h2>
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<p>A full design will consist of several different databases that are
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layered. Upper ones may override any content from a lower layer<br>
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</p>
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</p>
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<p><br>
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<p><br>
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<br>
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<br>
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<br>
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<br>
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<h2><a name="manifesto"></a>Database Guidelines</h2>
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<p></p>
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<p></p>
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<br>
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<p><img style="width: 800px; height: 600px;" alt=""
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<p><img style="width: 800px; height: 600px;" alt=""
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src="../png/data_fig1.png"><br>
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src="../png/data_fig1.png"><br>
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<br>
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<br>
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</p>
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</p>
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<p><br>
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<p><br>
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