Patent ID: 6938151
Filing Date: 2005-08-30
Classification: G06F

Abstract:
1. A method of predicting branch direction in a microprocessor, comprising the steps of providing branch prediction for a code sequence being executed by said microprocessor by use of one or more branch prediction processes including: (a) indexing based on the address of the branch, (b) accessing a global history register, (c) selecting between multiple predictors with a global selection counter, and in the process electing a process for predicting a specific branch by use of a prediction method comparison table (PMCT) to override, when appropriate, the global selection counter, wherein there is a global selection counter to select between the different history tables such that a single directional prediction can be made per branch, and said global selection counter has of a defined number of bits which represent the last number of branches equal to the value of two raised to this number of bits, which value increases or decreases towards certain ranges as a given branch predictor outperforms another predictor.