Branch prediction apparatus and branch prediction method
AssigneeFujitsu Limited
InventorMasaki Ukai
Life of this patent
Estimating the term…
Abstract
A branch history memory stores the branch history. The branch history represents the results in the past. When processing of a branch instruction is finished, a branch history update section updates the branch history corresponding to the branch instruction, based on the processing result. A branch history table update section updates the branch history in a branch history table. The branch history stores the number of recent continuous branching successful and the number recent of continuous branching failures.
Claims19
A branch prediction apparatus that predicts a target of a branch instruction using a branch history table, the branch history table storing a table of correspondence of an address of the branch instruction and a predicted target address of the branch instruction, the apparatus comprising:
- a branch history storage unit that stores a branch history, the branch history containing branching results in the past due to the branch instruction;
- and
- a branch history table update unit that predicts a branch direction of the branch instruction based on the branch history stored in the branch history storage unit, and updates the table of correspondence based on the predicted branch direction.
A branch prediction method of predicting a target of a branch instruction using a branch history table, the branch history table storing a table of correspondence of an address of the branch instruction and a predicted target address of the branch instruction, the method comprising:
- a branch history update step of storing a plurality of branch results of the branch instruction in the past as a branch history, and updating the stored branch history, at a point in time when the processing of the branch instruction has been finished, based on the processing result;
- and
- a branch history table update step of predicting a branch direction of the branch instruction based on the branch history updated at the branch history update step, and updating the table of correspondence based on the predicted branch direction.
Dependencies are inferred from the claim text.