# Copyright (c) 2007 The Regents of The University of Michigan
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import decimal

import sys
from m5.util import warn

# fix the global frequency
def fixGlobalFrequency():
    import _m5.core
    _m5.core.fixClockFrequency()

def setGlobalFrequency(ticksPerSecond):
    from m5.util import convert
    import _m5.core

    if isinstance(ticksPerSecond, int):
        tps = ticksPerSecond
    elif isinstance(ticksPerSecond, float):
        tps = ticksPerSecond
    elif isinstance(ticksPerSecond, str):
        tps = round(convert.anyToFrequency(ticksPerSecond))
    else:
        raise TypeError(
            "wrong type '%s' for ticksPerSecond" % type(ticksPerSecond))
    _m5.core.setClockFrequency(int(tps))

# how big does a rounding error need to be before we warn about it?
frequency_tolerance = 0.001  # 0.1%

def fromSeconds(value):
    import _m5.core

    if not isinstance(value, float):
        raise TypeError("can't convert '%s' to type tick" % type(value))

    # once someone needs to convert to seconds, the global frequency
    # had better be fixed
    if not _m5.core.clockFrequencyFixed():
        raise AttributeError(
              "In order to do conversions, the global frequency must be fixed")

    if value == 0:
        return 0

    # convert the value from time to ticks
    value *= _m5.core.getClockFrequency()

    int_value = int(
            decimal.Decimal(value).to_integral_value( decimal.ROUND_HALF_UP))
    err = (value - int_value) / value
    if err > frequency_tolerance:
        warn("rounding error > tolerance\n    %f rounded to %d", value,
            int_value)
    return int_value

__all__ = [ 'setGlobalFrequency', 'fixGlobalFrequency', 'fromSeconds',
            'frequency_tolerance' ]
