src/cpu/pred/BranchPredictor.py

   1 # Copyright (c) 2012 Mark D. Hill and David A. Wood
   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
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   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
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  19 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  21 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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  25 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26 #
  27 # Authors: Nilay Vaish
  28
  29 from m5.SimObject import SimObject
  30 from m5.params import *
  31
  32 class BranchPredictor(SimObject):
  33     type = 'BranchPredictor'
  34     cxx_class = 'BPredUnit'
  35     cxx_header = "cpu/pred/bpred_unit.hh"
  36
  37     numThreads = Param.Unsigned(1, "Number of threads")
  38     predType = Param.String("tournament",
  39         "Branch predictor type ('local', 'tournament')")
  40     localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
  41     localCtrBits = Param.Unsigned(2, "Bits per counter")
  42     localHistoryTableSize = Param.Unsigned(2048, "Size of local history table")
  43     globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
  44     globalCtrBits = Param.Unsigned(2, "Bits per counter")
  45     choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
  46     choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
  47
  48     BTBEntries = Param.Unsigned(4096, "Number of BTB entries")
  49     BTBTagSize = Param.Unsigned(16, "Size of the BTB tags, in bits")
  50
  51     RASSize = Param.Unsigned(16, "RAS size")
  52     instShiftAmt = Param.Unsigned(2, "Number of bits to shift instructions by")