| 摘要 |
<p>When a processor executes a memory operation instruction by means of data dependence speculative execution, reference is made to a speculative execution result history table 12 which stores accumulated information concerning success/failure results of the speculative execution of memory operation instructions, and thereby a prediction is made as to whether the present speculative execution will succeed or fail. In the prediction, the target address of the memory operation instruction is converted by a hash function circuit 11 into an entry number of the speculative execution result history table (allowing the existence of aliases), and reference is made to an entry of the table designated by the entry number. If the prediction is "success", the memory operation instruction is speculatively executed out-of-order (with regard to data dependence relationship between the instructions). If the prediction is "failure", the speculative execution is cancelled, and the memory operation instruction is non-speculatively executed later in the program order. Whether the speculative execution of the memory operation instructions has succeeded or failed is judged by detecting, 30, the data dependence relationship between the memory operation instructions, and the speculative execution result history table is updated taking the judgment into account.</p> |
