Method and apparatus for managing the execution of instructons with proximate successive branches in a cache-based data processing system

摘要

A small buffer called a branch-anticipate buffer (BAB) is used to store groups of instructions which are likely to be required from the instruction cache (I-cache) when an instruction prefetch miss occurs. When a prefetch miss occurs, the BAB is checked to see if instructions corresponding to the target address are available. If they are available, these instructions are copied into an appropriate buffer. If the instructions corresponding to the target address are unavailable, these instructions are fetched from the I-cache and placed into a buffer and, selectively, into the BAB. The BAB only maintains branch target addresses that have not been previously scanned and that cannot be prefetched in time. This allows for smaller buffer sizes, and resulting quicker access time, when checking the BAB for instructions to be executed by a processor.