| 摘要 |
PURPOSE:To improve the efficiency of paging control by constituting an LRU with plural reference bits. CONSTITUTION:An LRU 6 exists correspondingly to pages and consists of plural reference bits and outputs a reference bit, which corresponds to the input from a page table control part 4, to the page table control part 4 and an LRU update part 7. The LRU update part 7 checks the input from the LRU 6; and if the reference bit is turned off, it is turned on and the value obtained by adding one to contents of a page number register 8 is outputted to the page number register 8; but if the reference bit is turned on, contents are updated and are outputted to the LRU 6. Contents of the LRU 6 other than 0, namely, the number of accessed pages is held in the page number register 8. A comparing part 10 compares contents of the page number register 8 with those of a threshold register 9, and the LRU update part 7 is instructed to update the whole of the LRU 6 when the value of the page number register 8 exceeds that of the threshold register 9.
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