BranchPredictor.py revision 11429:cf5af0cc3be4 
1# Copyright (c) 2012 Mark D. Hill and David A. Wood
2# Copyright (c) 2015 The University of Wisconsin
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions are
7# met: redistributions of source code must retain the above copyright
8# notice, this list of conditions and the following disclaimer;
9# redistributions in binary form must reproduce the above copyright
10# notice, this list of conditions and the following disclaimer in the
11# documentation and/or other materials provided with the distribution;
12# neither the name of the copyright holders nor the names of its
13# contributors may be used to endorse or promote products derived from
14# this software without specific prior written permission.
15#
16# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27#
28# Authors: Nilay Vaish and Dibakar Gope
29
30from m5.SimObject import SimObject
31from m5.params import *
32
33class BranchPredictor(SimObject):
34    type = 'BranchPredictor'
35    cxx_class = 'BPredUnit'
36    cxx_header = "cpu/pred/bpred_unit.hh"
37    abstract = True
38
39    numThreads = Param.Unsigned(1, "Number of threads")
40    BTBEntries = Param.Unsigned(4096, "Number of BTB entries")
41    BTBTagSize = Param.Unsigned(16, "Size of the BTB tags, in bits")
42    RASSize = Param.Unsigned(16, "RAS size")
43    instShiftAmt = Param.Unsigned(2, "Number of bits to shift instructions by")
44
45
46class LocalBP(BranchPredictor):
47    type = 'LocalBP'
48    cxx_class = 'LocalBP'
49    cxx_header = "cpu/pred/2bit_local.hh"
50
51    localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
52    localCtrBits = Param.Unsigned(2, "Bits per counter")
53
54
55class TournamentBP(BranchPredictor):
56    type = 'TournamentBP'
57    cxx_class = 'TournamentBP'
58    cxx_header = "cpu/pred/tournament.hh"
59
60    localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
61    localCtrBits = Param.Unsigned(2, "Bits per counter")
62    localHistoryTableSize = Param.Unsigned(2048, "size of local history table")
63    globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
64    globalCtrBits = Param.Unsigned(2, "Bits per counter")
65    choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
66    choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
67
68
69class BiModeBP(BranchPredictor):
70    type = 'BiModeBP'
71    cxx_class = 'BiModeBP'
72    cxx_header = "cpu/pred/bi_mode.hh"
73
74    globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
75    globalCtrBits = Param.Unsigned(2, "Bits per counter")
76    choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
77    choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
78
79