Advanced Computer Architecture Chapter Q: Prediction

Advanced Computer Architecture, Imperial College 2001

Is local history all there is to it?

•The bimodal predictor uses the BHT to record “local history” - the prediction information used to predict a particular branch is determined only by its memory address

•Consider the following sequence:

if (C1) then

S1;

endif

if (C2) then

S2;

endif

if (C3) then

S3;

endif

¥It is very likely that condition C2 is correlated with C1 - and that C3 is correlated with C1 and C2 ¥How can we use this observation?