gem5/cpu/o3/sat_counter.cc

/*
 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * 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.
 */

#include "base/misc.hh"
#include "cpu/o3/sat_counter.hh"

SatCounter::SatCounter()
    : maxVal(0), counter(0)
{
}

SatCounter::SatCounter(unsigned bits)
    : maxVal((1 << bits) - 1), counter(0)
{
}

SatCounter::SatCounter(unsigned bits, unsigned initial_val)
    : maxVal((1 << bits) - 1), counter(initial_val)
{
    // Check to make sure initial value doesn't exceed the max counter value.
    if (initial_val > maxVal) {
        panic("BP: Initial counter value exceeds max size.");
    }
}

void
SatCounter::setBits(unsigned bits)
{
    maxVal = (1 << bits) - 1;
}

void
SatCounter::increment()
{
    if(counter < maxVal) {
        ++counter;
    }
}

void
SatCounter::decrement()
{
    if(counter > 0) {
        --counter;
    }
}