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diff --git a/src/mem/ruby/structures/PseudoLRUPolicy.cc b/src/mem/ruby/structures/PseudoLRUPolicy.cc
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+/*
+ * Copyright (c) 2013 Advanced Micro Devices, Inc
+ * 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;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * 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.
+ *
+ * Author: Derek Hower
+ */
+
+#include "mem/ruby/structures/PseudoLRUPolicy.hh"
+
+
+
+PseudoLRUPolicy::PseudoLRUPolicy(const Params * p)
+    : AbstractReplacementPolicy(p)
+{
+    // associativity cannot exceed capacity of tree representation
+    assert(m_num_sets > 0 &&
+           m_assoc > 1 &&
+           m_assoc <= (int64) sizeof(uint64)*4);
+
+    m_trees = NULL;
+    m_num_levels = 0;
+
+    m_effective_assoc = 1;
+    while (m_effective_assoc < m_assoc) {
+        // effective associativity is ceiling power of 2
+        m_effective_assoc <<= 1;
+    }
+    int tmp_assoc = m_effective_assoc;
+    while (true) {
+        tmp_assoc /= 2;
+        if(!tmp_assoc) break;
+        m_num_levels++;
+    }
+    assert(m_num_levels < sizeof(unsigned int)*4);
+    m_trees = new uint64[m_num_sets];
+    for (unsigned i = 0; i < m_num_sets; i++) {
+        m_trees[i] = 0;
+    }
+}
+
+PseudoLRUPolicy *
+PseudoLRUReplacementPolicyParams::create()
+{
+    return new PseudoLRUPolicy(this);
+}
+
+
+PseudoLRUPolicy::~PseudoLRUPolicy()
+{
+    if (m_trees != NULL)
+        delete[] m_trees;
+}
+
+void
+PseudoLRUPolicy::touch(int64 set, int64 index, Tick time)
+{
+    assert(index >= 0 && index < m_assoc);
+    assert(set >= 0 && set < m_num_sets);
+
+    int tree_index = 0;
+    int node_val;
+    for (int i = m_num_levels - 1; i >= 0; i--) {
+        node_val = (index >> i)&1;
+        if (node_val)
+            m_trees[set] |= node_val << tree_index;
+        else
+            m_trees[set] &= ~(1 << tree_index);
+        tree_index = node_val ? (tree_index*2)+2 : (tree_index*2)+1;
+    }
+    m_last_ref_ptr[set][index] = time;
+}
+
+int64
+PseudoLRUPolicy::getVictim(int64 set) const
+{
+    int64 index = 0;
+
+    int tree_index = 0;
+    int node_val;
+    for (unsigned i = 0; i < m_num_levels; i++){
+        node_val = (m_trees[set] >> tree_index) & 1;
+        index += node_val ? 0 : (m_effective_assoc >> (i + 1));
+        tree_index = node_val ? (tree_index * 2) + 1 : (tree_index * 2) + 2;
+    }
+    assert(index >= 0 && index < m_effective_assoc);
+
+    /* return either the found index or the max possible index */
+    /* NOTE: this is not a fair replacement when assoc is not a power of 2 */
+    return (index > (m_assoc - 1)) ? m_assoc - 1 : index;
+}