From: Maximilien Breughe <Maximilien.Breughe@elis.ugent.be>
Date: Fri, 14 May 2010 03:45:57 +0000 (-0400)
Subject: BPRED: Fixed the treshold-bug in the tournament predictor.
X-Git-Tag: stable_2012_02_02~1409^2~1
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=fc746c2268bfceded0014749cddd8234fa55a35a;p=gem5.git

BPRED: Fixed the treshold-bug in the tournament predictor.

Suppose the saturating counters of a branch predictor contain n bits.  When the
counter is between 0 and (2^(n-1) - 1), boundaries included, the branch is
predicted as not taken.  When the counter is between 2^(n-1) and (2^n - 1),
boundaries included, the branch is predicted as taken.
---

diff --git a/src/cpu/pred/tournament.cc b/src/cpu/pred/tournament.cc
index 223e45333..96ee87615 100644
--- a/src/cpu/pred/tournament.cc
+++ b/src/cpu/pred/tournament.cc
@@ -104,7 +104,6 @@ TournamentBP::TournamentBP(unsigned _localPredictorSize,
 
     // @todo: Allow for different thresholds between the predictors.
     threshold = (1 << (localCtrBits - 1)) - 1;
-    threshold = threshold / 2;
 }
 
 inline