sat_counter.cc

来自「linux下基于c++的处理器仿真平台。具有处理器流水线」· CC 代码 · 共 75 行

/*
 * Copyright (c) 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator, developed by Nathan Binkert,
 * Erik Hallnor, Steve Raasch, and Steve Reinhardt, with contributions
 * from Ron Dreslinski, Dave Greene, Lisa Hsu, Kevin Lim, Ali Saidi, 
 * and Andrew Schultz.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 */

#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;
    }
}