发明授权
- 专利标题: Method and apparatus for performing sequential executions of elements in cooperation with a transform
- 专利标题(中): 用于与变换协作执行元素的连续执行的方法和装置
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申请号: US09489072申请日: 2000-01-21
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公开(公告)号: US06715064B1公开(公告)日: 2004-03-30
- 发明人: Reynold V. D'Sa , Slade A. Morgan , Alan B. Kyker , Gad S. Sheaffer , Gustavo P. Espinosa
- 申请人: Reynold V. D'Sa , Slade A. Morgan , Alan B. Kyker , Gad S. Sheaffer , Gustavo P. Espinosa
- 主分类号: G06F1500
- IPC分类号: G06F1500
摘要:
A method and apparatus for predicting the outcome of a branch instruction based on the branch history of preceding branch instruction. As a sequence of instructions passes through an instruction execution pipeline, a base branch instruction is chosen, a history index is generated for the base branch instruction and subsequent branch instructions, and a transform is created for the branch instruction to be predicted. When the sequence of instructions subsequently passes through the pipeline again, the transform is used to operate on the history index of the base branch instruction to produce a history index for the branch to be predicted. The result is used as an index into a prediction array to access the prediction logic for the branch instruction being predicted. By using the predetermined transform, a branch status prediction can be made before the branch to be predicted reaches the normal prediction stage in the pipeline.
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