摘要： 转移指令，特别是条件转移指令是影响超标县处理器性能的关键。尽量减少转移指令所带来的损失，这是现今高性能处理器（如超标量处理器）设计中的关键问题一也是当今国际国内研究的热点。在众多的转移处理策略中，二级自适应预测（相关预测咽其相对性能最高而被广泛研究，且已被应用到商用处理器中。以一个程序为实例，通过踪迹驱动模拟分析了其局限性。并指出，多条件码和条件式执行技术与转移预测相结合，可减少条件转移指令和误预测率，提高处理器的性能。

关键词: 转移处理, 转移预测, 多条件码, 条件式执行

Abstract: Branch instruction has serious effect on the performance of superscalar microprocessor. Reducing the penaltyof branch nstruction is a key approach to improve the performance of superscalar microprocessor, and it is a hot area in theresearch field of computer architecture. Two Level Adaptive Branch Predictor has been studied extensively and has been incorporated into cufrently available microprocessor because it has the highest performance among existing branch handling strategies. In this paper, we analyzed the performance limitation of Two Level Adaptive Branch Prediction via trace simulatingtwo benchmark program. Furthermore, we pointed out that Multiple Condition Code and Conditional Execution can beused to reduce the number of static conditional branch instructions, as a result, the misprediction of dynamic predictor canbe reduced and the performance of processor also can be improved.

中图分类号: 

• TP332