xref: /gem5/src/systemc/channel/sc_semaphore.cc

/*
 * Copyright 2018 Google, Inc.
 *
 * 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.
 *
 * Authors: Gabe Black
 */

#include <string>

#include "base/logging.hh"
#include "systemc/ext/channel/messages.hh"
#include "systemc/ext/channel/sc_semaphore.hh"
#include "systemc/ext/core/sc_module.hh" // for sc_gen_unique_name
#include "systemc/ext/utils/sc_report_handler.hh"

namespace sc_core
{

sc_semaphore::sc_semaphore(int value) :
    sc_semaphore(sc_gen_unique_name("semaphore"), value)
{}

sc_semaphore::sc_semaphore(const char *_name, int value) :
        sc_interface(), sc_semaphore_if(), sc_object(_name), _value(value)
{
    if (value < 0) {
        std::string msg = "semaphore '" + std::string(name()) + "'";
        SC_REPORT_ERROR(SC_ID_INVALID_SEMAPHORE_VALUE_, msg.c_str());
    }
}

int
sc_semaphore::wait()
{
    while (trywait() == -1)
        ::sc_core::wait(posted);
    return 0;
}

int
sc_semaphore::trywait()
{
    if (!_value)
        return -1;

    _value--;
    return 0;
}

int
sc_semaphore::post()
{
    if (_value++ == 0)
        posted.notify();
    return 0;
}

int sc_semaphore::get_value() const { return _value; }

} // namespace sc_core