GB1231908A - - Google Patents

Abstract

1,231,908. Associative stores. INTERNATIONAL BUSINESS MACHINES CORP. 9 April, 1969, No. 18103/69. Heading G4C. An associative store comprises a plurality of input registers arranged to contain search arguments to be used in associative store accessing operations and control means arranged on every operation involving a search freely to select one or more of the input registers as the source of a search argument. In a first embodiment, either of two input registers can apply the search argument via a variable mask register to the store proper, and be used as an input/output register for a word being written or read, the mask register passing only those orders not used for the search argument during read/write. The operations are controlled by a decoder responsive to the input register contents. A second embodiment, capable of using different masks for a search than and subsequent read or write, does not use the input registers during read, the word read passing via either of two further mask registers connected respectively to buses connected to the input registers respectively. In modifications, the search argument is compiled in the (first) mask register by concatening non-overlapping fields from optionally different input registers, or by ANDing, ORing or EXCL-ORing corresponding bits from the two input registers. Another modification has two associative stores, each as above, with corresponding input registers connected to common buses, but with each input register only part of a word wide and one of the registers corresponding to a different part than the others so that characters from different words in one store can be concatenated into the same word in the other store. A plurality of associative stores may simultaneously provide respective characters of a word on a bus by suitable control of the output masking. Application of the invention to the stores of Specifications 1,186,703 and 1,127,270 is disclosed.