source: trunk/modules/vci_mem_cache_v2s/caba/source/include/mem_cache_directory_v2.h @ 41

#ifndef SOCLIB_CABA_MEM_CACHE_DIRECTORY_V2_H
#define SOCLIB_CABA_MEM_CACHE_DIRECTORY_V2_H 

#include <inttypes.h>
#include <systemc>
#include <cassert>
#include "arithmetics.h"

namespace soclib { namespace caba {

  using namespace sc_core;

  ////////////////////////////////////////////////////////////////////////
  //                    A LRU entry 
  ////////////////////////////////////////////////////////////////////////
  class LruEntry {

    public:

      bool recent;            

      void init()
      {
        recent=false;
      }

  }; // end class LruEntry

  ////////////////////////////////////////////////////////////////////////
  //                    A directory entry                               
  ////////////////////////////////////////////////////////////////////////
  class DirectoryEntry {

    typedef uint32_t tag_t;
    typedef uint32_t size_t;
    typedef uint32_t copy_t;

    public:

    bool    valid;                  // entry valid
    bool    is_cnt;                 // directory entry is a counter
    bool    dirty;                  // entry dirty
    bool    lock;                   // entry locked
    tag_t   tag;                    // tag of the entry
    copy_t  d_copies;               // vector of copies for data
    copy_t  i_copies;               // vector of copies for instructions
    size_t  count;                  // number of copies

    DirectoryEntry()
    {
      valid    = false;
      is_cnt   = false;
      dirty    = false;
      lock     = false;
      tag      = 0;
      d_copies = 0;
      i_copies = 0;
      count    = 0;
    }

    DirectoryEntry(const DirectoryEntry &source)
    {
      valid    = source.valid;
      is_cnt   = source.is_cnt;
      dirty    = source.dirty;
      tag      = source.tag;
      lock     = source.lock;
      d_copies = source.d_copies;
      i_copies = source.i_copies;
      count    = source.count;
    }          

    /////////////////////////////////////////////////////////////////////
    // The init() function initializes the entry 
    /////////////////////////////////////////////////////////////////////
    void init()
    {
      valid = false;
      is_cnt= false;
      dirty = false;
      lock  = false;
    }

    /////////////////////////////////////////////////////////////////////
    // The copy() function copies an existing source entry to a target 
    /////////////////////////////////////////////////////////////////////
    void copy(const DirectoryEntry &source)
    {
      valid     = source.valid;
      is_cnt    = source.is_cnt;
      dirty     = source.dirty;
      tag       = source.tag;
      lock      = source.lock;
      d_copies  = source.d_copies;
      i_copies  = source.i_copies;
      count     = source.count;
    }

    ////////////////////////////////////////////////////////////////////
    // The print() function prints the entry 
    ////////////////////////////////////////////////////////////////////
    void print()
    {
      std::cout << "Valid = " << valid << " ; IS COUNT = " << is_cnt << " ; Dirty = " << dirty << " ; Lock = " 
        << lock << " ; Tag = " << std::hex << tag << " ; d_copies = " << d_copies << " ; i_copies = " << i_copies << " ; count = " << count << std::endl;
    }

  }; // end class DirectoryEntry

  ////////////////////////////////////////////////////////////////////////
  //                       The directory  
  ////////////////////////////////////////////////////////////////////////
  class CacheDirectory {

    typedef sc_dt::sc_uint<40> addr_t;
    typedef uint32_t data_t;
    typedef uint32_t tag_t;
    typedef uint32_t size_t;

    private:

    // Directory constants
    size_t                                      m_ways;
    size_t                                      m_sets;
    size_t                                      m_words;
    size_t                                      m_width;

    // the directory & lru tables
    DirectoryEntry                              **m_dir_tab;
    LruEntry                                    **m_lru_tab;

    public:

    ////////////////////////
    // Constructor
    ////////////////////////
    CacheDirectory( size_t ways, size_t sets, size_t words, size_t address_width)        
    {
      m_ways  = ways; 
      m_sets  = sets;
      m_words = words;
      m_width = address_width;

      m_dir_tab = new DirectoryEntry*[sets];
      for ( size_t i=0; i<sets; i++ ) {
        m_dir_tab[i] = new DirectoryEntry[ways];
        for ( size_t j=0 ; j<ways ; j++) m_dir_tab[i][j].init();
      }
      m_lru_tab = new LruEntry*[sets];
      for ( size_t i=0; i<sets; i++ ) {
        m_lru_tab[i] = new LruEntry[ways];
        for ( size_t j=0 ; j<ways ; j++) m_lru_tab[i][j].init();
      }
    } // end constructor

    /////////////////
    // Destructor
    /////////////////
    ~CacheDirectory()
    {
      for(size_t i=0 ; i<m_sets ; i++){
        delete [] m_dir_tab[i];
        delete [] m_lru_tab[i];
      }
      delete [] m_dir_tab;
      delete [] m_lru_tab;
    } // end destructor

    /////////////////////////////////////////////////////////////////////
    // The read() function reads a directory entry. In case of hit, the
    // LRU is updated.
    // Arguments :
    // - address : the address of the entry 
    // - way : (return argument) the way of the entry in case of hit
    // The function returns a copy of a (valid or invalid) entry  
    /////////////////////////////////////////////////////////////////////
    DirectoryEntry read(const addr_t &address,size_t &way)
    {

#define L2 soclib::common::uint32_log2
      const size_t set = (size_t)(address >> (L2(m_words) + 2)) & (m_sets - 1);
      const tag_t  tag = (tag_t)(address >> (L2(m_sets) + L2(m_words) + 2));
#undef L2

      bool hit       = false;
      for ( size_t i=0 ; i<m_ways ; i++ ) {
        bool equal = ( m_dir_tab[set][i].tag == tag );
        bool valid = m_dir_tab[set][i].valid;
        hit = equal && valid;
        if ( hit ) {                    
          way = i;
          break;
        } 
      }
      if ( hit ) {
        m_lru_tab[set][way].recent = true;
        return DirectoryEntry(m_dir_tab[set][way]);
      } else {
        return DirectoryEntry();
      }
    } // end read()

    /////////////////////////////////////////////////////////////////////
    // The write function writes a new entry, 
    // and updates the LRU bits if necessary.
    // Arguments :
    // - set : the set of the entry
    // - way : the way of the entry
    // - entry : the entry value
    /////////////////////////////////////////////////////////////////////
    void write(const size_t &set, const size_t &way, const DirectoryEntry &entry)
    {
      assert( (set<m_sets) 
          && "Cache Directory write : The set index is invalid");
      assert( (way<m_ways) 
          && "Cache Directory write : The way index is invalid");

      // update Directory
      m_dir_tab[set][way].copy(entry);

      // update LRU bits
      bool all_recent = true;
      for ( size_t i=0 ; i<m_ways ; i++ ) {
        if ( i != way ) all_recent = m_lru_tab[set][i].recent && all_recent;
      }
      if ( all_recent ) {
        for( size_t i=0 ; i<m_ways ; i++ ) m_lru_tab[set][i].recent = false;
      } else {
        m_lru_tab[set][way].recent = true;
      }
    } // end write()

    /////////////////////////////////////////////////////////////////////
    // The print() function prints a selected directory entry
    // Arguments :
    // - set : the set of the entry to print
    // - way : the way of the entry to print
    /////////////////////////////////////////////////////////////////////
    void print(const size_t &set, const size_t &way)
    {
      std::cout << std::dec << " set : " << set << " ; way : " << way << " ; " ;
      m_dir_tab[set][way].print();
    } // end print()

    /////////////////////////////////////////////////////////////////////
    // The select() function selects a directory entry to evince.
    // Arguments :
    // - set   : (input argument) the set to modify
    // - way   : (return argument) the way to evince
    /////////////////////////////////////////////////////////////////////
    DirectoryEntry select(const size_t &set, size_t &way)
    {
      assert( (set < m_sets) 
          && "Cache Directory : (select) The set index is invalid");

      for(size_t i=0; i<m_ways; i++){
        if(!m_dir_tab[set][i].valid){
          way=i;
          return DirectoryEntry(m_dir_tab[set][way]);
        }
      }
      for(size_t i=0; i<m_ways; i++){
        if(!(m_lru_tab[set][i].recent) && !(m_dir_tab[set][i].lock)){
          way=i;
          return DirectoryEntry(m_dir_tab[set][way]);
        }
      }
      for(size_t i=0; i<m_ways; i++){
        if( !(m_lru_tab[set][i].recent) && (m_dir_tab[set][i].lock)){
          way=i;
          return DirectoryEntry(m_dir_tab[set][way]);
        }
      }
      for(size_t i=0; i<m_ways; i++){
        if( (m_lru_tab[set][i].recent) && !(m_dir_tab[set][i].lock)){
          way=i;
          return DirectoryEntry(m_dir_tab[set][way]);
        }
      }
      way = 0;
      return DirectoryEntry(m_dir_tab[set][0]);
    } // end select()

    /////////////////////////////////////////////////////////////////////
    //          Global initialisation function
    /////////////////////////////////////////////////////////////////////
    void init()
    {
      for ( size_t set=0 ; set<m_sets ; set++ ) {
        for ( size_t way=0 ; way<m_ways ; way++ ) {
          m_dir_tab[set][way].init();
          m_lru_tab[set][way].init();
        }
      }
    } // end init()

  }; // end class CacheDirectory

}} // end namespaces

#endif

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