| 摘要 |
<p>A branch prediction technique which increases the likelihood of correctly predicting the direction of a conditional branch instruction is presented. The technique is based on the observation that many branches have run lengths that are constant or slowly-varying, i.e. several consecutive runs of 1's are of the same length. The technique uses the history stored for each branch, which history is enhanced by two small counters (102, 113), an up counter (102) and a down counter (113). These counters (102, 113) operate in conjunction with a state machine branch predictor (101) of the prior art for very accurate predictions.</p> |
