In a high performance CPU there is no other way than a BTB hit
to know about a branch instruction and its type. For low-end CPU's
pre-decoding might sit in from of the BPU to provide this information.
Currently, the BPU models only low-end behavior and updates the
RAS and the indirect branch prediction even without a BTB hit.
This patch adds two things to model the correct behavior for high-end
CPUs.
1. A check before the RAS and indirect predictor wheather there was
a BTB hit or not. Only for BTB hits the BPU will consolidate RAS, and
indirect predictor.
2. Since, this check requires a BTB hit for indirect branches they must
also be installed into the BTB. For returns this was already done.
Change-Id: Ibef9aa890f180efe547c82f41fc71f457c988a89
Signed-off-by: David Schall <david.schall@ed.ac.uk>
94879c2410