GB1234038A - - Google Patents

Abstract

1,234,038. Associative stores. INTERNATIONAL COMPUTERS Ltd. 20 Jan., 1969 [30 Jan., 1968], No. 4737/68. Heading G4C. In an associative store, each cell R1-Rn comprises a data register D1-Dn and predecessor and successor registers P1-Pn and S1-Sn. Each predecessor register contains the address of the immediately preceding data register, and each successor register the address of the immediately succeeding data register, in the order of recency of accessing. A further register C1 (not shown) contains the address of the least recently accessed cell. When the store is to be accessed an identifier word is placed in register IB and compared at I1-In. with identifier words held in registers Il-In. If the required identifier is not in the store the words in the identifier and data registers IB, DB will replace the words in corresponding registers of the least recently accessed cell, and the address in register C1 will be replaced by the address in the predecessor register of the cell least recently accessed, i.e. by the address of the cell now least recently accessed. If, on the other hand, the required identifier is in the store the corresponding data register is accessed. Should this register be in the cell least recently accessed register C1 is updated, but if it is not the addresses in the predecessor and successor registers of the cell are replaced by the addresses in the predecessor register of the cell most recently accessed and in the successor register of the cell least recently accessed, respectively, these latter two registers then being filled with the address of the cell being accessed.