Virtual addressing apparatus for addressing the memory of a computer utilizing associative addressing techniques

Apparatus for forming an absolute address for accessing a memory of a computer comprising, in combination:

• a plurality of ordered register means each being capable of storing a respective associative word, each associative word having a respective absolute page identifier and a respective virtual page identifier, said register means being arranged in sequential order;
• read means for sequentially reading associative words from said memory into the highest ordered register means;
• shift means for sequentially shifting associative words from a higher ordered register means to a lower ordered register means;
• receiver means for receiving a virtual address from a job program, said virtual address having a virtual page identifier and a virtual word identifier;
• compare means connected to said receiver means and at least one of said register means for comparing the virtual page identifier of said virtual address in said receiver means with the virtual page identifier in said one of said register means, said compare means providing a signal indicative of the correspondence or non-correspondence between the virtual page identifier of said virtual address and the virtual page identifier of the associative word in said any of said register means;
• first control means, responsive to the signal indicative that said compare means senses a correspondence between the virtual page identifier of said virtual address and a virtual page identifier of an associative word,
• for transferring the associative word containing the corresponding virtual page identifier from a lower ordered register means to the highest ordered register means, and
• for operating said shift means to shift associative words, previously stored in register means having a higher order than the said lower ordered register means from which the transferred associative word was transferred, to the next lower ordered register means;
• and
• storage address register means responsive to said compare means for storing the absolute page identifier of the associative word containing said corresponding virtual page identifier.