ticks.py revision 4762:c94e103c83ad
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 29import sys 30 31tps = 1.0e12 # default to 1 THz (1 Tick == 1 ps) 32tps_fixed = False # once set to true, can't be changed 33 34# fix the global frequency and tell C++ about it 35def fixGlobalFrequency(): 36 import internal 37 global tps, tps_fixed 38 if not tps_fixed: 39 tps_fixed = True 40 internal.core.setClockFrequency(int(tps)) 41 print "Global frequency set at %d ticks per second" % int(tps) 42 43def setGlobalFrequency(ticksPerSecond): 44 import convert 45 46 global tps, tps_fixed 47 48 if tps_fixed: 49 raise AttributeError, \ 50 "Global frequency already fixed at %f ticks/s." % tps 51 52 if isinstance(ticksPerSecond, (int, long)): 53 tps = ticksPerSecond 54 elif isinstance(ticksPerSecond, float): 55 tps = ticksPerSecond 56 elif isinstance(ticksPerSecond, str): 57 tps = round(convert.anyToFrequency(ticksPerSecond)) 58 else: 59 raise TypeError, \ 60 "wrong type '%s' for ticksPerSecond" % type(ticksPerSecond) 61 62# how big does a rounding error need to be before we warn about it? 63frequency_tolerance = 0.001 # 0.1% 64 65def fromSeconds(value): 66 if not isinstance(value, float): 67 raise TypeError, "can't convert '%s' to type tick" % type(value) 68 69 # once someone needs to convert to seconds, the global frequency 70 # had better be fixed 71 if not tps_fixed: 72 raise AttributeError, \ 73 "In order to do conversions, the global frequency must be fixed" 74 75 if value == 0: 76 return 0 77 78 # convert the value from time to ticks 79 value *= tps 80 81 int_value = int(round(value)) 82 err = (value - int_value) / value 83 if err > frequency_tolerance: 84 print >>sys.stderr, "Warning: rounding error > tolerance" 85 print >>sys.stderr, " %f rounded to %d" % (value, int_value) 86 return int_value 87 88__all__ = [ 'setGlobalFrequency', 'fixGlobalFrequency', 'fromSeconds', 89 'frequency_tolerance' ] 90