| 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 first table, a second table, and selection logic. The first table stores branch histories for a first set of branch instructions where the first branch instructions are categorized within the first table according to a first outcome bias. The second table stores branch histories for a second set of branch instructions, where the second branch instructions are categorized within the second table according to a second outcome bias. The selection logic is coupled to the first and second tables. When a branch instruction is executed by the microprocessor, the selection logic selects a particular branch history to predict the outcome of the branch instruction. Thus, a branch prediction is made based upon contents of a branch history that is selected from a table containing branch histories for other branch instructions that are categorized according to similar outcome bias, thereby reducing the negative effects of aliasing.
|
