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37 * Authors: Andreas Hansson
42 * ClockedObject declaration and implementation.
45 #ifndef __SIM_CLOCKED_OBJECT_HH__
46 #define __SIM_CLOCKED_OBJECT_HH__
48 #include "base/intmath.hh"
49 #include "base/misc.hh"
50 #include "params/ClockedObject.hh"
51 #include "sim/core.hh"
52 #include "sim/sim_object.hh"
55 * The ClockedObject class extends the SimObject with a clock and
56 * accessor functions to relate ticks to the cycles of the object.
58 class ClockedObject : public SimObject
63 // the tick value of the next clock edge (>= curTick()) at the
64 // time of the last call to update()
67 // The cycle counter value corresponding to the current value of
72 * Prevent inadvertent use of the copy constructor and assignment
73 * operator by making them private.
75 ClockedObject(ClockedObject&);
76 ClockedObject& operator=(ClockedObject&);
79 * Align cycle and tick to the next clock edge if not already done.
83 // both tick and cycle are up-to-date and we are done, note
84 // that the >= is important as it captures cases where tick
85 // has already passed curTick()
86 if (tick >= curTick())
89 // optimise for the common case and see if the tick should be
90 // advanced by a single clock period
94 // see if we are done at this point
95 if (tick >= curTick())
98 // if not, we have to recalculate the cycle and tick, we
99 // perform the calculations in terms of relative cycles to
100 // allow changes to the clock period in the future
101 Cycles elapsedCycles(divCeil(curTick() - tick, clock));
102 cycle += elapsedCycles;
103 tick += elapsedCycles * clock;
106 // Clock period in ticks
112 * Create a clocked object and set the clock based on the
115 ClockedObject(const ClockedObjectParams* p) :
116 SimObject(p), tick(0), cycle(0), clock(p->clock)
119 fatal("%s has a clock period of zero\n", name());
124 * Virtual destructor due to inheritance.
126 virtual ~ClockedObject() { }
129 * Reset the object's clock using the current global tick value. Likely
130 * to be used only when the global clock is reset. Currently, this done
131 * only when Ruby is done warming up the memory system.
133 void resetClock() const
135 Cycles elapsedCycles(divCeil(curTick(), clock));
136 cycle = elapsedCycles;
137 tick = elapsedCycles * clock;
143 * Determine the tick when a cycle begins, by default the current
144 * one, but the argument also enables the caller to determine a
147 * @param cycles The number of cycles into the future
149 * @return The tick when the clock edge occurs
151 inline Tick clockEdge(Cycles cycles = Cycles(0)) const
153 // align tick to the next clock edge
156 // figure out when this future cycle is
157 return tick + clock * cycles;
161 * Determine the current cycle, corresponding to a tick aligned to
164 * @return The current cycle count
166 inline Cycles curCycle() const
168 // align cycle to the next clock edge.
175 * Based on the clock of the object, determine the tick when the
176 * next cycle begins, in other words, return the next clock edge.
178 * @return The tick when the next cycle starts
180 Tick nextCycle() const
181 { return clockEdge(); }
183 inline uint64_t frequency() const { return SimClock::Frequency / clock; }
185 inline Tick clockPeriod() const { return clock; }
187 inline Cycles ticksToCycles(Tick t) const
188 { return Cycles(t / clock); }
192 #endif //__SIM_CLOCKED_OBJECT_HH__