Summary: Anatomy of a Branch Predictor

Prog. Exec.

Event selec.

Pred. Index.

Pred. Mechan.

Feedback

Recovery?

All instructions (BTB) Branch inst. (BPT)

PC and/or global history and/or local history

One level (BPT) Two level (History +PHT) Decoupled BTB + BPT

Static (ISA) 1 or 2-bit saturating counters

Branch outcome Update pred. mechanism Update history (updates might be speculative)