clocked_object.hh revision 9356
17506Stjones1@inf.ed.ac.uk/* 27506Stjones1@inf.ed.ac.uk * Copyright (c) 2012 ARM Limited 37506Stjones1@inf.ed.ac.uk * All rights reserved 47506Stjones1@inf.ed.ac.uk * 57506Stjones1@inf.ed.ac.uk * The license below extends only to copyright in the software and shall 67506Stjones1@inf.ed.ac.uk * not be construed as granting a license to any other intellectual 77506Stjones1@inf.ed.ac.uk * property including but not limited to intellectual property relating 87506Stjones1@inf.ed.ac.uk * to a hardware implementation of the functionality of the software 97506Stjones1@inf.ed.ac.uk * licensed hereunder. You may use the software subject to the license 107506Stjones1@inf.ed.ac.uk * terms below provided that you ensure that this notice is replicated 117506Stjones1@inf.ed.ac.uk * unmodified and in its entirety in all distributions of the software, 127506Stjones1@inf.ed.ac.uk * modified or unmodified, in source code or in binary form. 137506Stjones1@inf.ed.ac.uk * 147506Stjones1@inf.ed.ac.uk * Redistribution and use in source and binary forms, with or without 157506Stjones1@inf.ed.ac.uk * modification, are permitted provided that the following conditions are 167506Stjones1@inf.ed.ac.uk * met: redistributions of source code must retain the above copyright 177506Stjones1@inf.ed.ac.uk * notice, this list of conditions and the following disclaimer; 187506Stjones1@inf.ed.ac.uk * redistributions in binary form must reproduce the above copyright 197506Stjones1@inf.ed.ac.uk * notice, this list of conditions and the following disclaimer in the 207506Stjones1@inf.ed.ac.uk * documentation and/or other materials provided with the distribution; 217506Stjones1@inf.ed.ac.uk * neither the name of the copyright holders nor the names of its 227506Stjones1@inf.ed.ac.uk * contributors may be used to endorse or promote products derived from 237506Stjones1@inf.ed.ac.uk * this software without specific prior written permission. 247506Stjones1@inf.ed.ac.uk * 257506Stjones1@inf.ed.ac.uk * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 267506Stjones1@inf.ed.ac.uk * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 277506Stjones1@inf.ed.ac.uk * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 287506Stjones1@inf.ed.ac.uk * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 297506Stjones1@inf.ed.ac.uk * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 307506Stjones1@inf.ed.ac.uk * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 317506Stjones1@inf.ed.ac.uk * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 327506Stjones1@inf.ed.ac.uk * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 337506Stjones1@inf.ed.ac.uk * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 347506Stjones1@inf.ed.ac.uk * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 357506Stjones1@inf.ed.ac.uk * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 367698SAli.Saidi@ARM.com * 377506Stjones1@inf.ed.ac.uk * Authors: Andreas Hansson 387506Stjones1@inf.ed.ac.uk */ 397506Stjones1@inf.ed.ac.uk 407506Stjones1@inf.ed.ac.uk/** 417506Stjones1@inf.ed.ac.uk * @file 427506Stjones1@inf.ed.ac.uk * ClockedObject declaration and implementation. 437506Stjones1@inf.ed.ac.uk */ 447506Stjones1@inf.ed.ac.uk 457506Stjones1@inf.ed.ac.uk#ifndef __SIM_CLOCKED_OBJECT_HH__ 467506Stjones1@inf.ed.ac.uk#define __SIM_CLOCKED_OBJECT_HH__ 477506Stjones1@inf.ed.ac.uk 487506Stjones1@inf.ed.ac.uk#include "base/intmath.hh" 497506Stjones1@inf.ed.ac.uk#include "params/ClockedObject.hh" 507506Stjones1@inf.ed.ac.uk#include "sim/core.hh" 517506Stjones1@inf.ed.ac.uk#include "sim/sim_object.hh" 527506Stjones1@inf.ed.ac.uk 537506Stjones1@inf.ed.ac.uk/** 547506Stjones1@inf.ed.ac.uk * The ClockedObject class extends the SimObject with a clock and 557720Sgblack@eecs.umich.edu * accessor functions to relate ticks to the cycles of the object. 567506Stjones1@inf.ed.ac.uk */ 577506Stjones1@inf.ed.ac.ukclass ClockedObject : public SimObject 588787Sgblack@eecs.umich.edu{ 598787Sgblack@eecs.umich.edu 608787Sgblack@eecs.umich.edu private: 618787Sgblack@eecs.umich.edu 628787Sgblack@eecs.umich.edu // the tick value of the next clock edge (>= curTick()) at the 638787Sgblack@eecs.umich.edu // time of the last call to update() 648787Sgblack@eecs.umich.edu mutable Tick tick; 657693SAli.Saidi@ARM.com 667693SAli.Saidi@ARM.com // The cycle counter value corresponding to the current value of 677693SAli.Saidi@ARM.com // 'tick' 687693SAli.Saidi@ARM.com mutable Cycles cycle; 697693SAli.Saidi@ARM.com 707693SAli.Saidi@ARM.com /** 717693SAli.Saidi@ARM.com * Prevent inadvertent use of the copy constructor and assignment 727811Ssteve.reinhardt@amd.com * operator by making them private. 73 */ 74 ClockedObject(ClockedObject&); 75 ClockedObject& operator=(ClockedObject&); 76 77 /** 78 * Align cycle and tick to the next clock edge if not already done. 79 */ 80 void update() const 81 { 82 // both tick and cycle are up-to-date and we are done, note 83 // that the >= is important as it captures cases where tick 84 // has already passed curTick() 85 if (tick >= curTick()) 86 return; 87 88 // optimise for the common case and see if the tick should be 89 // advanced by a single clock period 90 tick += clock; 91 ++cycle; 92 93 // see if we are done at this point 94 if (tick >= curTick()) 95 return; 96 97 // if not, we have to recalculate the cycle and tick, we 98 // perform the calculations in terms of relative cycles to 99 // allow changes to the clock period in the future 100 Cycles elapsedCycles(divCeil(curTick() - tick, clock)); 101 cycle += elapsedCycles; 102 tick += elapsedCycles * clock; 103 } 104 105 protected: 106 107 // Clock period in ticks 108 Tick clock; 109 110 /** 111 * Create a clocked object and set the clock based on the 112 * parameters. 113 */ 114 ClockedObject(const ClockedObjectParams* p) : 115 SimObject(p), tick(0), cycle(0), clock(p->clock) 116 { } 117 118 /** 119 * Virtual destructor due to inheritance. 120 */ 121 virtual ~ClockedObject() { } 122 123 /** 124 * Reset the object's clock using the current global tick value. Likely 125 * to be used only when the global clock is reset. Currently, this done 126 * only when Ruby is done warming up the memory system. 127 */ 128 void resetClock() const 129 { 130 Cycles elapsedCycles(divCeil(curTick(), clock)); 131 cycle = elapsedCycles; 132 tick = elapsedCycles * clock; 133 } 134 135 public: 136 137 /** 138 * Determine the tick when a cycle begins, by default the current 139 * one, but the argument also enables the caller to determine a 140 * future cycle. 141 * 142 * @param cycles The number of cycles into the future 143 * 144 * @return The tick when the clock edge occurs 145 */ 146 inline Tick clockEdge(Cycles cycles = Cycles(0)) const 147 { 148 // align tick to the next clock edge 149 update(); 150 151 // figure out when this future cycle is 152 return tick + clock * cycles; 153 } 154 155 /** 156 * Determine the current cycle, corresponding to a tick aligned to 157 * a clock edge. 158 * 159 * @return The current cycle count 160 */ 161 inline Cycles curCycle() const 162 { 163 // align cycle to the next clock edge. 164 update(); 165 166 return cycle; 167 } 168 169 /** 170 * Based on the clock of the object, determine the tick when the 171 * next cycle begins, in other words, return the next clock edge. 172 * 173 * @return The tick when the next cycle starts 174 */ 175 Tick nextCycle() const 176 { return clockEdge(); } 177 178 inline uint64_t frequency() const { return SimClock::Frequency / clock; } 179 180 inline Tick clockPeriod() const { return clock; } 181 182 inline Cycles ticksToCycles(Tick tick) const 183 { return Cycles(tick / clock); } 184 185}; 186 187#endif //__SIM_CLOCKED_OBJECT_HH__ 188