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+// $Id: roundrobin_arb.hpp 5188 2012-08-30 00:31:31Z dub $
+
+/*
+ Copyright (c) 2007-2012, Trustees of The Leland Stanford Junior University
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ Redistributions of source code must retain the above copyright notice, this 
+ list of conditions and the following disclaimer.
+ Redistributions in binary form must reproduce the above copyright notice, this
+ list of conditions and the following disclaimer in the documentation and/or
+ other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+// ----------------------------------------------------------------------
+//
+//  RoundRobin: Round Robin Arbiter
+//
+// ----------------------------------------------------------------------
+
+#ifndef _ROUNDROBIN_HPP_
+#define _ROUNDROBIN_HPP_
+
+#include "arbiter.hpp"
+
+class RoundRobinArbiter : public Arbiter {
+
+  // Priority pointer
+  int  _pointer ;
+
+public:
+
+  // Constructors
+  RoundRobinArbiter( Module *parent, const string &name, int size ) ;
+
+  // Print priority matrix to standard output
+  virtual void PrintState() const ;
+  
+  // Update priority matrix based on last aribtration result
+  virtual void UpdateState() ; 
+
+  // Arbitrate amongst requests. Returns winning input and 
+  // updates pointers to metadata when valid pointers are passed
+  virtual int Arbitrate( int* id = 0, int* pri = 0) ;
+
+  virtual void AddRequest( int input, int id, int pri ) ;
+
+  virtual void Clear();
+
+  static inline bool Supersedes(int input1, int pri1, int input2, int pri2, int offset, int size)
+  {
+    // in a round-robin scheme with the given number of positions and current 
+    // offset, should a request at input1 with priority pri1 supersede a 
+    // request at input2 with priority pri2?
+    return ((pri1 > pri2) || 
+	    ((pri1 == pri2) && 
+	     (((input1 - offset + size) % size) < ((input2 - offset + size) % size))));
+  }
+  
+} ;
+
+#endif