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#ifndef __SYSTEMC_EXT_TLM_UTILS_TLM_QUANTUMKEEPER_H__
#define __SYSTEMC_EXT_TLM_UTILS_TLM_QUANTUMKEEPER_H__
#include <tlm>
namespace tlm_utils
{
// tlm_quantumkeeper class
//
// The tlm_quantumkeeper class is used to keep track of the local time in
// an initiator (how much it has run ahead of the SystemC time), to
// synchronize with SystemC time etc.
class tlm_quantumkeeper
{
public:
//
// Static setters/getters for the global quantum value.
//
// The global quantum is the maximum time an initiator can run ahead of
// SystemC time. All initiators will synchronize on timing points that are
// multiples of the global quantum value.
//
static void
set_global_quantum(const sc_core::sc_time &t)
{
tlm::tlm_global_quantum::instance().set(t);
}
static const sc_core::sc_time &
get_global_quantum()
{
return tlm::tlm_global_quantum::instance().get();
}
public:
tlm_quantumkeeper() : m_next_sync_point(sc_core::SC_ZERO_TIME),
m_local_time(sc_core::SC_ZERO_TIME)
{}
virtual ~tlm_quantumkeeper() {}
// Increment the local time (the time the initiator is ahead of the
// systemC time) After incrementing the local time an initiator should
// check (with the need_sync method) if a sync is required.
virtual void inc(const sc_core::sc_time &t) { m_local_time += t; }
// Sets the local time (the time the initiator is ahead of the
// systemC time) After changing the local time an initiator should
// check (with the need_sync method) if a sync is required.
virtual void set(const sc_core::sc_time &t) { m_local_time = t; }
// Checks if a sync to systemC is required for this initiator. This will
// be the case if the local time becomes greater than the local (current)
// quantum value for this initiator.
virtual bool
need_sync() const
{
return sc_core::sc_time_stamp() + m_local_time >= m_next_sync_point;
}
// Synchronize to systemC. This call will do a wait for the time the
// initiator was running ahead of systemC time and reset the
// tlm_quantumkeeper.
virtual void
sync()
{
sc_core::wait(m_local_time);
reset();
}
// Non-virtual convenience method to set the local time and sync only if
// needed
void
set_and_sync(const sc_core::sc_time &t)
{
set(t);
if (need_sync())
sync();
}
// Resets the local time to SC_ZERO_TIME and computes the value of the
// next local quantum. This method should be called by an initiator after
// a wait because of a synchronization request by a target (TLM_ACCEPTED,
// or TLM_UPDATED).
virtual void
reset()
{
m_local_time = sc_core::SC_ZERO_TIME;
m_next_sync_point = sc_core::sc_time_stamp() + compute_local_quantum();
}
// Helper function to get the current systemC time, taken the local time
// into account. The current systemC time is calculated as the time
// returned by sc_time_stamp incremeneted with the time the initiator is
// running ahead.
virtual sc_core::sc_time
get_current_time() const
{
return sc_core::sc_time_stamp() + m_local_time;
}
// Helper functions to get the time the initiator is running ahead of
// systenC (local time). This time should be passed to a target in the
// nb_transport call
virtual sc_core::sc_time
get_local_time() const
{
return m_local_time;
}
protected:
// Calculate the next local quantum for this initiator.
//
// The method can be overloaded in a derived object if an initiator wants
// to use another local quantum. This derived object should also take the
// global quantum into account. It's local quantum should not be set to a
// value that is larger than the quantum returned by the
// compute_local_quantum of the tlm_global_quantum singleton.
virtual sc_core::sc_time
compute_local_quantum()
{
return tlm::tlm_global_quantum::instance().compute_local_quantum();
}
protected:
sc_core::sc_time m_next_sync_point;
sc_core::sc_time m_local_time;
};
} // namespace tlm_utils
#endif /* __SYSTEMC_EXT_TLM_UTILS_TLM_QUANTUMKEEPER_H__ */