| 摘要 |
An apparatus and method are provided for accurately predicting the outcome of branch instructions prior to their execution by a pipeline microprocessor. The apparatus includes a bias indicator and a dynamic branch predictor. The bias indicator receives a branch instruction from an instruction buffer and provides an output indicating a particular outcome bias category for the branch instruction. The bias indicator provides the output as a function of a branch type and a displacement, where the branch type and the displacement are prescribed by the branch instruction The dynamic branch predictor is coupled to the bias indicator. The dynamic branch predictor receives the output and predicts an outcome for the branch instruction based upon contents of an entry in a particular branch history table, where the particular branch history table corresponds to the particular outcome bias category, and where the dynamic branch predictor maintains a plurality of branch history tables, each of the plurality of branch history tables corresponding to an outcome bias category, and where the outcome bias category is selected from a plurality of outcome bias categories, and where the plurality of outcome bias categories comprises a taken category and a not taken category.
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