| 摘要 |
A data processing system (20) is able to perform parameter-selectable prefetch instructions to prefetch data for a cache (38). When attempting to be backward compatible with previously written code, sometimes performing this instruction can result in attempting to prefetch redundant data by prefetching the same data twice. In order to prevent this, the parameters of the instruction are analyzed to determine if such redundant data will be prefetched. If so, then the parameters are altered to avoid prefetching redundant data. In some of the possibilities for the parameters of the instruction, the altering of the parameters requires significant circuitry so that an alternative approach is used. This alternative but slower approach, which can be used in the same system with the first approach, detects if the line of the cache that is currently being requested is the same as the previous request. If so, the current request is not executed. |
