xref: /gem5/src/mem/ruby/structures/TimerTable.cc

/*
 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
 * 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.
 */

/*
 * $Id$
 */

#include "mem/ruby/common/Global.hh"
#include "mem/ruby/system/TimerTable.hh"
#include "mem/ruby/eventqueue/RubyEventQueue.hh"

TimerTable::TimerTable()
{
  m_consumer_ptr  = NULL;
  m_next_valid = false;
  m_next_address = Address(0);
  m_next_time = 0;
}


bool TimerTable::isReady() const
{
  if (m_map.size() == 0) {
    return false;
  }

  if (!m_next_valid) {
    updateNext();
  }
  assert(m_next_valid);
  return (g_eventQueue_ptr->getTime() >= m_next_time);
}

const Address& TimerTable::readyAddress() const
{
  assert(isReady());

  if (!m_next_valid) {
    updateNext();
  }
  assert(m_next_valid);
  return m_next_address;
}

void TimerTable::set(const Address& address, Time relative_latency)
{
  assert(address == line_address(address));
  assert(relative_latency > 0);
  assert(m_map.exist(address) == false);
  Time ready_time = g_eventQueue_ptr->getTime() + relative_latency;
  m_map.add(address, ready_time);
  assert(m_consumer_ptr != NULL);
  g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, ready_time);
  m_next_valid = false;

  // Don't always recalculate the next ready address
  if (ready_time <= m_next_time) {
    m_next_valid = false;
  }
}

void TimerTable::unset(const Address& address)
{
  assert(address == line_address(address));
  assert(m_map.exist(address) == true);
  m_map.remove(address);

  // Don't always recalculate the next ready address
  if (address == m_next_address) {
    m_next_valid = false;
  }
}

void TimerTable::print(ostream& out) const
{
}


void TimerTable::updateNext() const
{
  if (m_map.size() == 0) {
    assert(m_next_valid == false);
    return;
  }

  Vector<Address> addresses = m_map.keys();
  m_next_address = addresses[0];
  m_next_time = m_map.lookup(m_next_address);

  // Search for the minimum time
  int size = addresses.size();
  for (int i=1; i<size; i++) {
    Address maybe_next_address = addresses[i];
    Time maybe_next_time = m_map.lookup(maybe_next_address);
    if (maybe_next_time < m_next_time) {
      m_next_time = maybe_next_time;
      m_next_address= maybe_next_address;
    }
  }
  m_next_valid = true;
}