Cache memory device with fast data-write capacity

Claim 1

A cache memory device to be placed between a processor and a main memory in a computer, comprising: data memory means for storing selected data stored in said main memory, one of said selected data in said data memory means, which is located at an address in said data memory means corresponding to a processor address to which said processor is making an access, being superseded as a superseded one of said selected data by one of processor data from said processor at a particular process cycle when said access by said processor is for a data-write process, and a group of a plurality of data among said selected data being stored as a block of data in said data memory means; hit/miss detector means for determining, at said particular process cycle, said access as a hit when said access is made with respect to a correct address in said data memory means, and as a miss otherwise; means for memorizing said superseded one of said selected data at said address in said data memory means corresponding to said processor address when said access for said data-write process is made; copy-back memory means for storing one block of data which contained said superseded one of said selected data in said data memory means in an original state before said data-write process took place; and selector means for selecting said superseded one of said selected data memorized in said means for memorizing as an input, corresponding to said processor address, to said copy-back memory means at another process cycle later than said particular process cycle only when said access was determined as a miss, such that said one block in said original state before said data-write process is reconstructed in said copy-back memory means.