ticks.py revision 13719:74853963ddcf 
1# Copyright (c) 2007 The Regents of The University of Michigan
2# All rights reserved.
3#
4# Redistribution and use in source and binary forms, with or without
5# modification, are permitted provided that the following conditions are
6# met: redistributions of source code must retain the above copyright
7# notice, this list of conditions and the following disclaimer;
8# redistributions in binary form must reproduce the above copyright
9# notice, this list of conditions and the following disclaimer in the
10# documentation and/or other materials provided with the distribution;
11# neither the name of the copyright holders nor the names of its
12# contributors may be used to endorse or promote products derived from
13# this software without specific prior written permission.
14#
15# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26#
27# Authors: Nathan Binkert
28
29from __future__ import print_function
30import six
31if six.PY3:
32    long = int
33
34import sys
35from m5.util import warn
36
37# fix the global frequency
38def fixGlobalFrequency():
39    import _m5.core
40    _m5.core.fixClockFrequency()
41
42def setGlobalFrequency(ticksPerSecond):
43    from m5.util import convert
44    import _m5.core
45
46    if isinstance(ticksPerSecond, (int, long)):
47        tps = ticksPerSecond
48    elif isinstance(ticksPerSecond, float):
49        tps = ticksPerSecond
50    elif isinstance(ticksPerSecond, str):
51        tps = round(convert.anyToFrequency(ticksPerSecond))
52    else:
53        raise TypeError(
54            "wrong type '%s' for ticksPerSecond" % type(ticksPerSecond))
55    _m5.core.setClockFrequency(int(tps))
56
57# how big does a rounding error need to be before we warn about it?
58frequency_tolerance = 0.001  # 0.1%
59
60def fromSeconds(value):
61    import _m5.core
62
63    if not isinstance(value, float):
64        raise TypeError("can't convert '%s' to type tick" % type(value))
65
66    # once someone needs to convert to seconds, the global frequency
67    # had better be fixed
68    if not _m5.core.clockFrequencyFixed():
69        raise AttributeError(
70              "In order to do conversions, the global frequency must be fixed")
71
72    if value == 0:
73        return 0
74
75    # convert the value from time to ticks
76    value *= _m5.core.getClockFrequency()
77
78    int_value = int(round(value))
79    err = (value - int_value) / value
80    if err > frequency_tolerance:
81        warn("rounding error > tolerance\n    %f rounded to %d", value,
82            int_value)
83    return int_value
84
85__all__ = [ 'setGlobalFrequency', 'fixGlobalFrequency', 'fromSeconds',
86            'frequency_tolerance' ]
87