BRANCH TARGET BUFFER ALLOCATION

摘要

A data processing system (10) and method are provided for allocating an entry in a branch target buffer (BTB) (14). The method comprises: receiving a branch instruction to be executed in a data processor(40); determining that the BTB does not include an entry corresponding to the branch instruction; identifying an entry in the BTB for allocation, the identified entry in the BTB comprising a target identifier (30) and a first prediction value (32) for a previously received branch instruction; determining whether to allocate the branch instruction to the identified entry in the BTB based on a comparison of the first prediction value to a second prediction value, wherein the second prediction value is generated from a branch history table (BHT) (20); and allocating the branch instruction to the identified entry if the second prediction value indicates a more strongly taken prediction than the first prediction value.