Conley, Rose & Tayon, P.C.
Pipelined instruction cache and branch prediction mechanism therefor
 A microprocessor includes an instruction cache having a cache access time greater than the clock cycle time employed by the microprocessor. The instruction cache is banked, and access to alternate banks is pipelined. The microprocessor also includes a branch prediction unit. The branch prediction unit provides a branch prediction in response to each fetch address. The branch prediction predicts a non-consecutive instruction block within the instruction stream being executed by the microprocessor. Access to the consecutive instruction block is initiated prior to completing access to a current instruction block. Therefore, a branch prediction for the consecutive instruction block is produced as a result of fetching a prior instruction block. A branch prediction produced as a result of fetching the current instruction block predicts the non-consecutive instruction block, and the fetch address of the non-consecutive instruction block is provided to the instruction cache access pipeline. 
Advanced Micro Devices, Inc.
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Thang M.
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