src/mem/cache/tags/repl/repl.hh

   1 /*
   2  * Copyright (c) 2002-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Erik Hallnor
  29  *          Steve Reinhardt
  30  *          Nathan Binkert
  31  */
  32
  33 /**
  34  * @file
  35  * Declaration of a base replacement policy class.
  36  */
  37
  38 #ifndef __REPL_HH__
  39 #define __REPL_HH__
  40
  41 #include <string>
  42 #include <list>
  43
  44 #include "cpu/smt.hh"
  45 #include "sim/host.hh"
  46 #include "sim/sim_object.hh"
  47
  48
  49 class IIC;
  50
  51 /**
  52  * A pure virtual base class that defines the interface of a replacement
  53  * policy.
  54  */
  55 class Repl : public SimObject
  56 {
  57  public:
  58     /** Pointer to the IIC using this policy. */
  59     IIC *iic;
  60
  61     /**
  62      * Construct and initialize this polixy.
  63      * @param name The instance name of this policy.
  64      */
  65     Repl (const std::string &name)
  66         : SimObject(name)
  67     {
  68         iic = NULL;
  69     }
  70
  71     /**
  72      * Set the back pointer to the IIC.
  73      * @param iic_ptr Pointer to the IIC.
  74      */
  75     void setIIC(IIC *iic_ptr)
  76     {
  77         iic = iic_ptr;
  78     }
  79
  80     /**
  81      * Returns the tag pointer of the cache block to replace.
  82      * @return The tag to replace.
  83      */
  84     virtual unsigned long getRepl() = 0;
  85
  86     /**
  87      * Return an array of N tag pointers to replace.
  88      * @param n The number of tag pointer to return.
  89      * @return An array of tag pointers to replace.
  90      */
  91     virtual unsigned long  *getNRepl(int n) = 0;
  92
  93     /**
  94      * Update replacement data
  95      */
  96     virtual void doAdvance(std::list<unsigned long> &demoted) = 0;
  97
  98      /**
  99      * Add a tag to the replacement policy and return a pointer to the
 100      * replacement entry.
 101      * @param tag_index The tag to add.
 102      * @return The replacement entry.
 103      */
 104     virtual void* add(unsigned long tag_index) = 0;
 105
 106     /**
 107      * Register statistics.
 108      * @param name The name to prepend to statistic descriptions.
 109      */
 110     virtual void regStats(const std::string name) = 0;
 111
 112     /**
 113      * Update the tag pointer to when the tag moves.
 114      * @param re The replacement entry of the tag.
 115      * @param old_index The old tag pointer.
 116      * @param new_index The new tag pointer.
 117      * @return 1 if successful, 0 otherwise.
 118      */
 119     virtual int fixTag(void *re, unsigned long old_index,
 120                        unsigned long new_index) = 0;
 121
 122     /**
 123      * Remove this entry from the replacement policy.
 124      * @param re The replacement entry to remove
 125      */
 126     virtual void removeEntry(void *re) = 0;
 127 };
 128
 129 #endif /* SMT_REPL_HH */