| 摘要 |
PURPOSE:To control the replacement of data on the basis of an LPU method by constituting a storage part in each storage block with a shift register and forming a control circuit for controlling the shift of only the optional number of data in the registers from the 1st storage block to the succeeding steps. CONSTITUTION:Each of storage blocks 1-5 is constituted of a register 26 and a comparator 27. A control circuit 28 is constituted of NOR circuits 6-14, inverter circuits 15-19 and transmission gates 20-24 to control shift operation among the registers 26. The data used most recently are always stored in the storage block 1 and the succeeding data are successively stored after the storage block 2 in accordance with the used order, and if data which are not stored in any storage block are used, the data of the registers in all the storage blocks are shifted to the succeeding steps and the oldest used data stored in the storage block 5 are deleted. Thus, the buffer memory device of which data can be replaced on the basis of the LRU method can be obtained.
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