xref: /gem5/src/systemc/ext/dt/fx/sc_context.hh

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/*****************************************************************************

  sc_context.h -

  Original Author: Martin Janssen, Synopsys, Inc.

 *****************************************************************************/

/*****************************************************************************

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

      Name, Affiliation, Date:
  Description of Modification:

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// $Log: sc_context.h,v $
// Revision 1.2  2011/08/24 22:05:43  acg
//  Torsten Maehne: initialization changes to remove warnings.
//
// Revision 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.5  2006/05/26 20:36:52  acg
//  Andy Goodrich: added a using for sc_core::default_ptr_hash_fn to keep HP
//  aCC happy.
//
// Revision 1.4  2006/03/21 00:00:31  acg
//   Andy Goodrich: changed name of sc_get_current_process_base() to be
//   sc_get_current_process_b() since its returning an sc_process_b instance.
//
// Revision 1.3  2006/01/13 18:53:57  acg
// Andy Goodrich: added $Log command so that CVS comments are reproduced in
// the source.
//

#ifndef __SYSTEMC_EXT_DT_FX_SC_CONTEXT_HH__
#define __SYSTEMC_EXT_DT_FX_SC_CONTEXT_HH__

#include <map>

#include "../../core/sc_process_handle.hh"
#include "../../utils/sc_report_handler.hh"

namespace sc_dt
{

// classes defined in this module
class sc_without_context;
template <class T>
class sc_global;
template <class T>
class sc_context;


// ----------------------------------------------------------------------------
//  CLASS : sc_without_context
//
//  Empty class that is used for its type only.
// ----------------------------------------------------------------------------

class sc_without_context {};


// ----------------------------------------------------------------------------
//  TEMPLATE CLASS : sc_global
//
//  Template global variable class; singleton; co-routine safe.
// ----------------------------------------------------------------------------

template <class T>
class sc_global
{
    sc_global();
    void update();

  public:
    static sc_global<T>* instance();
    const T*& value_ptr();

  private:
    static sc_global<T> *m_instance;

    std::map<void *, const T *> m_map;
    void *m_proc; // context (current process or NULL)
    const T *m_value_ptr;
};


// ----------------------------------------------------------------------------
//  ENUM : sc_context_begin
//
//  Enumeration of context begin options.
// ----------------------------------------------------------------------------

enum sc_context_begin
{
    SC_NOW,
    SC_LATER
};


// ----------------------------------------------------------------------------
//  CLASS : sc_context
//
//  Template context class; co-routine safe.
// ----------------------------------------------------------------------------

template <class T>
class sc_context
{
    // disabled
    sc_context(const sc_context<T> &);
    void *operator new(std::size_t);

  public:
    explicit sc_context(const T &, sc_context_begin=SC_NOW);
    ~sc_context();

    void begin();
    void end();

    static const T &default_value();
    const T &value() const;

  private:
    sc_context &operator = (const sc_context &) /* = delete */;

    const T m_value;
    const T *&m_def_value_ptr;
    const T *m_old_value_ptr;
};


// IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

// ----------------------------------------------------------------------------
//  TEMPLATE CLASS : sc_global
//
//  Template global variable class; singleton; co-routine safe.
// ----------------------------------------------------------------------------

template <class T>
sc_global<T> *sc_global<T>::m_instance = 0;

template <class T>
inline sc_global<T>::sc_global() : m_map(),
    // use &m_instance as unique "non-process" key (NULL denotes 'sc_main'
    // context)
    m_proc(&m_instance), m_value_ptr(0)
{}


template <class T>
inline void
sc_global<T>::update()
{
    void *p = (::sc_gem5::Process *)sc_core::sc_get_current_process_handle();
    if (p != m_proc) {
        const T *vp = m_map[p];
        if (vp == 0) {
            vp = new T(sc_without_context());
            m_map.emplace(p, vp);
        }
        m_proc = p;
        m_value_ptr = vp;
    }
}


template <class T>
inline sc_global<T> *
sc_global<T>::instance()
{
    if (m_instance == 0) {
        m_instance = new sc_global<T>;
    }
    return m_instance;
}


template <class T>
inline const T *&
sc_global<T>::value_ptr()
{
    update();
    return m_value_ptr;
}


// ----------------------------------------------------------------------------
//  CLASS : sc_context
//
//  Template context class; co-routine safe.
// ----------------------------------------------------------------------------

template <class T>
inline sc_context<T>::sc_context(const T &value_, sc_context_begin begin_) :
        m_value(value_),
        m_def_value_ptr(sc_global<T>::instance()->value_ptr()),
        m_old_value_ptr(0)
{
    if (begin_ == SC_NOW) {
        m_old_value_ptr = m_def_value_ptr;
        m_def_value_ptr = &m_value;
    }
}

template <class T>
inline sc_context<T>::~sc_context()
{
    if (m_old_value_ptr != 0) {
        m_def_value_ptr = m_old_value_ptr;
        m_old_value_ptr = 0;
    }
}


template <class T>
inline void
sc_context<T>::begin()
{
    if (m_old_value_ptr == 0) {
        m_old_value_ptr = m_def_value_ptr;
        m_def_value_ptr = &m_value;
    } else {
        SC_REPORT_ERROR("context begin failed", 0);
    }
}

template <class T>
inline void
sc_context<T>::end()
{
    if (m_old_value_ptr != 0) {
        m_def_value_ptr = m_old_value_ptr;
        m_old_value_ptr = 0;
    } else {
        SC_REPORT_ERROR("context end failed", 0);
    }
}


template <class T>
inline const T &
sc_context<T>::default_value()
{
    return *sc_global<T>::instance()->value_ptr();
}

template <class T>
inline const T &
sc_context<T>::value() const
{
    return m_value;
}

} // namespace sc_dt

#endif // __SYSTEMC_EXT_DT_FX_SC_CONTEXT_HH__