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

Claim 2

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.

Claim 3

Apparatus according to claim 1 further including means for storing the word identifier from said virtual address in said storage address register means.

Claim 4

Apparatus according to claim 1 wherein said associative words each contain a use code, said first control means being responsive to a predetermined use code in an associative word stored in one of said register means for further operating said shift means to shift said associative word from said one register means to a lower ordered register means from where an associative word was transferred to the highest ordered register means.

Claim 5

Apparatus according to claim 3 further including means for storing the word identifier from said virtual address in said storage address register means.

Claim 6

Apparatus according to claim 1 further including write means for writing associative words into said memory from said plurality of register means, second control means, responsive to the signal indicative that said compare means senses a non-correspondence between the virtual page identifier of said virtual address and a virtual page identifier of an associative word in said register means, for selectively operating said write means to sequentially write associative words to said memory from all of said register means except the lowest ordered register means, and for operating said read means to sequentially read additional associative words from said memory into the highest ordered register means, and for operating said shift means to shift said additional associative words to lower ordered register means, said compare means comparing the virtual page identifier of said virtual address with the virtual page identifier in said one register means for providing a further signal indicative of the correspondence between the virtual page identifier of said virtual address and the virtual page identifier of the additional associative word in said any of said register means, said second control means being responsive to said further signal to operate said write means to write all associative words stored in said plurality of register means into said memory except that associative word containing virtual page identifier which corresponds to the virtual page identifier in said virtual address, and to operate said read means to sequentially read back to said register means those associative words which were written into said memory under control of said second control means when said second control means responded to the first-named signal, and to operate said shift means to shift the associative word containing the virtual page identifier which corresponds to the virtual page identifier in said virtual address to the highest ordered register means, whereby the associative word containing the virtual page identifier corresponding to the virtual page identifier of virtual address is thereupon stored in the highest ordered register means, the associative words previously stored in all except the lowest ordered register means are thereupon stored in sequence in the register means next following the highest ordered register means, and the associative word previously stored in the lowest ordered register means is thereupon stored in memory in a higher ordered position than said additional associative words written into said memory from said register means.

Claim 7

Apparatus according to claim 5 futher including means for storing the word identifier from said virtual address in said storage address register means.

Claim 8

Apparatus according to claim 5 wherein said associative words each contain a use code, said first control means being responsive to a predetermined use code in an associative word stored in one of said register means for further operating said shift means to shift said associative word from said one register means to a lower ordered register means from where an associative word was transferred to the highest ordered register means.

Claim 9

Apparatus according to claim 7 further including means for storing the word identifier from said virtual address in said storage address register means.