src/sim/simulate.cc

   1 /*
   2  * Copyright (c) 2006 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Nathan Binkert
  29  *          Steve Reinhardt
  30  */
  31
  32 #include "base/misc.hh"
  33 #include "base/pollevent.hh"
  34 #include "sim/stat_control.hh"
  35 #include "sim/async.hh"
  36 #include "sim/eventq.hh"
  37 #include "sim/host.hh"
  38 #include "sim/sim_events.hh"
  39 #include "sim/sim_exit.hh"
  40 #include "sim/simulate.hh"
  41
  42 /** Simulate for num_cycles additional cycles.  If num_cycles is -1
  43  * (the default), do not limit simulation; some other event must
  44  * terminate the loop.  Exported to Python via SWIG.
  45  * @return The SimLoopExitEvent that caused the loop to exit.
  46  */
  47 SimLoopExitEvent *
  48 simulate(Tick num_cycles)
  49 {
  50     inform("Entering event queue @ %d.  Starting simulation...\n", curTick);
  51
  52     if (num_cycles < 0)
  53         fatal("simulate: num_cycles must be >= 0 (was %d)\n", num_cycles);
  54     else if (curTick + num_cycles < 0)  //Overflow
  55         num_cycles = MaxTick;
  56     else
  57         num_cycles = curTick + num_cycles;
  58
  59     Event *limit_event =
  60         new SimLoopExitEvent("simulate() limit reached", 0);
  61     mainEventQueue.schedule(limit_event, num_cycles);
  62
  63     while (1) {
  64         // there should always be at least one event (the SimLoopExitEvent
  65         // we just scheduled) in the queue
  66         assert(!mainEventQueue.empty());
  67         assert(curTick <= mainEventQueue.nextTick() &&
  68                "event scheduled in the past");
  69
  70         // forward current cycle to the time of the first event on the
  71         // queue
  72         curTick = mainEventQueue.nextTick();
  73         Event *exit_event = mainEventQueue.serviceOne();
  74         if (exit_event != NULL) {
  75             // hit some kind of exit event; return to Python
  76             // event must be subclass of SimLoopExitEvent...
  77             SimLoopExitEvent *se_event;
  78             se_event = dynamic_cast<SimLoopExitEvent *>(exit_event);
  79
  80             if (se_event == NULL)
  81                 panic("Bogus exit event class!");
  82
  83             // if we didn't hit limit_event, delete it
  84             if (se_event != limit_event) {
  85                 assert(limit_event->scheduled());
  86                 limit_event->squash();
  87                 hack_once("be nice to actually delete the event here");
  88             }
  89
  90             return se_event;
  91         }
  92
  93         if (async_event) {
  94             async_event = false;
  95             if (async_statdump || async_statreset) {
  96                 Stats::StatEvent(async_statdump, async_statreset);
  97                 async_statdump = false;
  98                 async_statreset = false;
  99             }
 100
 101             if (async_exit) {
 102                 async_exit = false;
 103                 exitSimLoop("user interrupt received");
 104             }
 105
 106             if (async_io || async_alarm) {
 107                 async_io = false;
 108                 async_alarm = false;
 109                 pollQueue.service();
 110             }
 111
 112             if (async_exception) {
 113                 async_exception = false;
 114                 return NULL;
 115             }
 116         }
 117     }
 118
 119     // not reached... only exit is return on SimLoopExitEvent
 120 }
 121