JPS61147445U

JPS61147445U -

Info

Publication number: JPS61147445U
Application number: JP1900786U
Authority: JP
Priority date: 1986-02-13
Filing date: 1986-02-13
Publication date: 1986-09-11

Description

[Brief explanation of the drawing]

第１図はリプレイス制御装置の概略構成を示す
図、第２図は４ウエイのアクセス歴の古さを示す
ＬＲＵビツトの論理図、第３図はＬＲＵ情報の構
成例の説明図、第４図ａ，ｂ，ｃは同順位をもつ
ＬＲＵ情報の説明図、第５図は本考案の実施例回
路の構成図、第６図乃至第９図は第５図の実施例
回路において使用できる論理回路の例を示す図で
ある。図中、８は古さを示す矢印の本数ｐが２以上の
ウエイを選択する論理回路、９はｐ≧２のウエイ
の数ｑが１つの場合の該ウエイを検出する論理回
路、１０はｑ＝２の場合また１１はｑ＝３の場合
のウエイを検出する論理回路、１２はＯＲ回路を
示す。 Fig. 1 is a diagram showing a schematic configuration of the replacement control device, Fig. 2 is a logic diagram of LRU bits showing the age of 4-way access history, Fig. 3 is an explanatory diagram of an example of the structure of LRU information, and Fig. 4 a, b, c are explanatory diagrams of LRU information having the same rank, FIG. 5 is a configuration diagram of an embodiment circuit of the present invention, and FIGS. 6 to 9 are logic circuits that can be used in the embodiment circuit of FIG. 5. FIG. In the figure, 8 is a logic circuit that selects a way in which the number p of arrows indicating age is 2 or more, 9 is a logic circuit that detects a way when the number q of ways with p≧2 is 1, and 10 is q In the case of q=2, 11 is a logic circuit for detecting the way in the case of q=3, and 12 is an OR circuit.

Claims

[Scope of utility model registration request]

In a buffer storage device equipped with a control device that determines a replacement way using LRU information consisting of LRU bits indicating the age of access history between each way, a first logic circuit that examines a plurality of corresponding LRU bits between and outputs the way as a replacement candidate way when a certain number or more of the bits indicate that the way is old; a second logic circuit that selects one replacement candidate way outputted from the first logic circuit; and a second logic circuit that selects the replacement candidate way outputted from the first logic circuit; and a second logic circuit that selects the replacement candidate way outputted from the first logic circuit; When there are three replacement candidate ways output from the third logic circuit and the first logic circuit, which selects the older way among the candidate ways, a set of two replacement candidate ways among them is selected according to a predetermined logic. The fourth way selects the older way between the two ways.
1. A replace way control circuit comprising: a logic circuit, and determining a way selected by each of the logic circuits as a replace way.