1# Copyright (c) 2005-2007 The Regents of The University of Michigan
2# Copyright (c) 2010-2013 Advanced Micro Devices, Inc.
3# Copyright (c) 2013 Mark D. Hill and David A. Wood
4# All rights reserved.
5#
6# Redistribution and use in source and binary forms, with or without
7# modification, are permitted provided that the following conditions are
8# met: redistributions of source code must retain the above copyright
9# notice, this list of conditions and the following disclaimer;
10# redistributions in binary form must reproduce the above copyright
11# notice, this list of conditions and the following disclaimer in the
12# documentation and/or other materials provided with the distribution;
13# neither the name of the copyright holders nor the names of its
14# contributors may be used to endorse or promote products derived from
15# this software without specific prior written permission.
16#
17# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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20# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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23# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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27# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28#
29# Authors: Nathan Binkert
30
31from m5.SimObject import SimObject
32from m5.params import *
33from m5.util import fatal
34
35class Root(SimObject):
36
37    _the_instance = None
38
39    def __new__(cls, **kwargs):
40        if Root._the_instance:
41            fatal("Attempt to allocate multiple instances of Root.")
42            return None
43
44        # first call: allocate the unique instance
45        #
46        # If SimObject ever implements __new__, we may want to pass
47        # kwargs here, but for now this goes straight to
48        # object.__new__ which prints an ugly warning if you pass it
49        # args.  Seems like a bad design but that's the way it is.
50        Root._the_instance = SimObject.__new__(cls)
51        return Root._the_instance
52
53    @classmethod
54    def getInstance(cls):
55        return Root._the_instance
56
57    def path(self):
58        return 'root'
59
60    type = 'Root'
61    cxx_header = "sim/root.hh"
62
63    # By default, root sim object and hence all other sim objects schedule
64    # event on the eventq with index 0.
65    eventq_index = 0
66
67    # Simulation Quantum for multiple main event queue simulation.
68    # Needs to be set explicitly for a multi-eventq simulation.
69    sim_quantum = Param.Tick(0, "simulation quantum")
70
71    full_system = Param.Bool("if this is a full system simulation")
72
73    # Time syncing prevents the simulation from running faster than real time.
74    time_sync_enable = Param.Bool(False, "whether time syncing is enabled")
75    time_sync_period = Param.Clock("100ms", "how often to sync with real time")
76    time_sync_spin_threshold = \
77            Param.Clock("100us", "when less than this much time is left, spin")
78