Branch prediction tables and buffers

• Branch prediction table (BPT or branch history table BHT)

  • How addressed (low-order bits of PC, hashing, cache-like)
  • How much history in the prediction (1-bit, 2-bits, n-bits)
  • Where is it stored (in a separate table, associated with the I-cache)

• Branch target buffers (BTB)

  • BPT + address of target instruction (+ target instruction -- not implemented in current micros as far as I know--)

• Correlated branch prediction

  • 2-level prediction

• Hybrid predictors

  • Choose dynamically the best among 2 predictors

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