dwt.hpp

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/*
 * OpenMPTL - C++ Microprocessor Template Library
 *
 * Copyright (C) 2012-2017 Axel Burri <axel@tty0.ch>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef ARM_CORTEX_COMMON_DWT_HPP_INCLUDED
#define ARM_CORTEX_COMMON_DWT_HPP_INCLUDED

#include "reg/dwt.hpp"
#include "reg/debug.hpp"

namespace mptl {

class dwt
{
public:

  static void enable(void) {
    DEBUG::DEMCR::TRCENA::set();
  }

  static void disable(void) {
    DEBUG::DEMCR::TRCENA::clear();
  }

  static void cycle_counter_enable(void) {
    DWT::CYCCNT::store(0); // reset counter
    DWT::CTRL::set(1);     // enable counter
  }

  static DWT::CYCCNT::value_type cycle_counter_load(void) {
    return DWT::CYCCNT::load();
  }
};


/**
 * Cycle counter: Count processor clock cycles
 */
class cycle_counter
{
  using value_type = decltype(dwt::cycle_counter_load());

  value_type value;

public:

  cycle_counter(void) : value(0) {
    dwt::enable();
    dwt::cycle_counter_enable();
  }

  ~cycle_counter(void) {
    dwt::disable();
  }

  void start(void) {
    value = dwt::cycle_counter_load();
  }

  void stop(void) {
    value = dwt::cycle_counter_load() - value;
  }

  value_type get(void) {
    return value;
  }
};

} // namespace mptl

#endif // ARM_CORTEX_COMMON_DWT_HPP_INCLUDED