Cache memory address apparatus
First Claim
1. A cache memory address apparatus for use in a processing system producing virtual addresses, cache addresses corresponding to respective virtual addresses, and physical addresses translated from said virtual addresses, said apparatus comprising:
- cache address storage means for storing a first portion of a cache address at a first cache address storage location that is addressed by a first portion of a virtual address to which said cache address corresponds and for storing a second portion of said cache address at a second cache address storage location that is addressed by a second portion of said virtual address;
gate means responsive to information stored in said cache address storage locations for providing a miss signal when either one of said cache address storage locations addressed by said virtual address does not contain a corresponding cache address portion which corresponds to said portion of said virtual address and for providing an enabling signal when said first and second cache address storage locations addressed by said virtual address contain first and second cache address portions which correspond, respectively, to said first and second portions of said virtual address; and
physical address storage means having a plurality of addressable storage locations for storing physical address portions at locations addressed by cache addresses formed from cache address portions stored in said cache address storage means and for providing, in response to said enabling signal, a physical address portion stored at a location addressed by said cache address.
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Accused Products
Abstract
In a processor system with a virtual memory organization and a cache memory table storing the physical addresses corresponding to the most-recenty used virtual addresses, access to the cache table is enhanced by associating upper and lower MSB portions of a virtual address with corresponding upper and lower portions of an associated cache address. The separate cache address portions are placed in separate cache address storage devices. Each cache address storage device is addressed by respective virtual address MSB portions. A physical address storage device stores physical addresses translated from virtual addresses in storage locations addressed by cache addresses associated with the respective virtual addresses from which the physical addresses were translated.
49 Citations
7 Claims
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1. A cache memory address apparatus for use in a processing system producing virtual addresses, cache addresses corresponding to respective virtual addresses, and physical addresses translated from said virtual addresses, said apparatus comprising:
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cache address storage means for storing a first portion of a cache address at a first cache address storage location that is addressed by a first portion of a virtual address to which said cache address corresponds and for storing a second portion of said cache address at a second cache address storage location that is addressed by a second portion of said virtual address; gate means responsive to information stored in said cache address storage locations for providing a miss signal when either one of said cache address storage locations addressed by said virtual address does not contain a corresponding cache address portion which corresponds to said portion of said virtual address and for providing an enabling signal when said first and second cache address storage locations addressed by said virtual address contain first and second cache address portions which correspond, respectively, to said first and second portions of said virtual address; and physical address storage means having a plurality of addressable storage locations for storing physical address portions at locations addressed by cache addresses formed from cache address portions stored in said cache address storage means and for providing, in response to said enabling signal, a physical address portion stored at a location addressed by said cache address. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for storing physical addresses in a system producing virtual addresses, cache addresses corresponding to respective virtual addresses, and physical addresses translated from said virtual addresses, comprising the steps of:
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storing, for a virtual address, first and second portions of a corresponding cache address at first and second cache address storage location, respectively, addressed by first and second portions, respectively, of said virtual address; entering, at said first and second cache address storage location, flag data indicating said storage; determining based upon the presence or absence of flag data, whether said first and second cache address storage locations addressed by said first and second portions of said virtual address contain first and second cache address portions; storing, at a physical address storage location addressed by said stored cache address, a physical address portion translated form said virtual address; and if said first and second cache address storage location addressed by said portions of said virtual address are determined to contain first and second cache address portions, retrieving the physical address portion stored at said physical address location.
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Specification