Integrating a misprediction recovery cache (MRC) into a superscalar pipeline

In modern processors, deep pipelines couple with superscalar techniques to allow each pipe stage to process multiple instructions. When such a pipe must be pushed and refilled, as when predicted program flow beyond a branch is subsequently recognized as wrong, the temporary performance loss is significant. While modern branch target buffer (BTB) technology makes this flush/refill penalty fairly rare, the penalty that accrues from the remaining branch mispredictions is a serious impediment to even higher processor performance. Advanced mechanisms that can reduce this residual misprediction penalty can be of enormous value in future microprocessor designs. One promising new mechanism, the Misprediction Recovery Cache (MRC) is proposed previously. In this paper, we focus especially on MRC integration into existing pipelines