src/mem/ruby/filters/BlockBloomFilter.cc

   1 /*
   2  * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
   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
  29 #include "base/intmath.hh"
  30 #include "base/str.hh"
  31 #include "mem/ruby/filters/BlockBloomFilter.hh"
  32 #include "mem/ruby/system/System.hh"
  33
  34 using namespace std;
  35
  36 BlockBloomFilter::BlockBloomFilter(string str)
  37 {
  38     string head, tail;
  39
  40 #ifndef NDEBUG
  41     bool success =
  42 #endif
  43         split_first(str, head, tail, '_');
  44
  45     assert(success);
  46
  47     m_filter_size = atoi(head.c_str());
  48     m_filter_size_bits = floorLog2(m_filter_size);
  49
  50     m_filter.resize(m_filter_size);
  51
  52     clear();
  53 }
  54
  55 BlockBloomFilter::~BlockBloomFilter()
  56 {
  57 }
  58
  59 void
  60 BlockBloomFilter::clear()
  61 {
  62     for (int i = 0; i < m_filter_size; i++) {
  63         m_filter[i] = 0;
  64     }
  65 }
  66
  67 void
  68 BlockBloomFilter::increment(const Address& addr)
  69 {
  70     // Not used
  71 }
  72
  73 void
  74 BlockBloomFilter::decrement(const Address& addr)
  75 {
  76     // Not used
  77 }
  78
  79 void
  80 BlockBloomFilter::merge(AbstractBloomFilter * other_filter)
  81 {
  82     // TODO
  83 }
  84
  85 void
  86 BlockBloomFilter::set(const Address& addr)
  87 {
  88     int i = get_index(addr);
  89     m_filter[i] = 1;
  90 }
  91
  92 void
  93 BlockBloomFilter::unset(const Address& addr)
  94 {
  95     int i = get_index(addr);
  96     m_filter[i] = 0;
  97 }
  98
  99 bool
 100 BlockBloomFilter::isSet(const Address& addr)
 101 {
 102     int i = get_index(addr);
 103     return (m_filter[i]);
 104 }
 105
 106 int
 107 BlockBloomFilter::getCount(const Address& addr)
 108 {
 109     return m_filter[get_index(addr)];
 110 }
 111
 112 int
 113 BlockBloomFilter::getTotalCount()
 114 {
 115     int count = 0;
 116
 117     for (int i = 0; i < m_filter_size; i++) {
 118         if (m_filter[i]) {
 119             count++;
 120         }
 121     }
 122     return count;
 123 }
 124
 125 int
 126 BlockBloomFilter::getIndex(const Address& addr)
 127 {
 128     return get_index(addr);
 129 }
 130
 131 void
 132 BlockBloomFilter::print(ostream& out) const
 133 {
 134 }
 135
 136 int
 137 BlockBloomFilter::readBit(const int index)
 138 {
 139     return m_filter[index];
 140 }
 141
 142 void
 143 BlockBloomFilter::writeBit(const int index, const int value)
 144 {
 145     m_filter[index] = value;
 146 }
 147
 148 int
 149 BlockBloomFilter::get_index(const Address& addr)
 150 {
 151     // Pull out some bit field ==> B1
 152     // Pull out additional bits, not the same as B1 ==> B2
 153     //  XOR B1 and B2 to get hash index
 154     physical_address_t block_bits =
 155         addr.bitSelect(RubySystem::getBlockSizeBits(),
 156                        2 * RubySystem::getBlockSizeBits() - 1);
 157     int offset = 5;
 158     physical_address_t other_bits =
 159         addr.bitSelect(2 * RubySystem::getBlockSizeBits() + offset,
 160                        2 * RubySystem::getBlockSizeBits() + offset +
 161                        m_filter_size_bits - 1);
 162     int index = block_bits ^ other_bits;
 163     assert(index < m_filter_size);
 164     return index;
 165 }
 166
 167