| 摘要 |
PURPOSE:To improve a hit rate of a translation lookaside buffer (TLB) by dividing the TLB into a user use and a common area use, also, dividing that of the user use into main and sub-buffers, replacing and using the main buffer and that of the common area use, in case a fault has been generated in the buffer of the common area use, having a high use frequency, and controlling this operation by a flag. CONSTITUTION:A switching flag F which has been outputted from a flag use register 1 is checked by a comparing circuit 4. In case of the switching flag F=1, a value of a logical address 3 and a value of a register 2 for an address to be compared are compared 5. In case the logical address 3 is not an address of a common area, a main TLB 7 is selected by a selector 6 by a comparator 5 and a value of the switching flag F, and the main TLB 7 and a sub-TLB 8 are brought to an access. In case of an address of the common area, a TLB 9 for the common area is selected and brought to an access. Also, in case of the switching flag F=0, the TLB 9 for the common area, and the main TLB 7 are used as the main TLB and the buffer for the common area use, respectively.
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