Lookup table addressing system and method
AssigneeAnalog Devices, Inc.
InventorsJames Wilson, Joshua A. Kablotsky, Yosef Stein, Christopher M. Mayer
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Abstract
Lookup table addressing of a set of lookup tables in an external memory is achieved by: transferring a data word from a compute unit to an input register in a data address generator; providing in at least one deposit-increment index register in the data address generator including a table base field for identifying the location of the set of tables in memory, and a displacement field; and depositing a section of the data word into a displacement field in the index register for identifying the location of a specific entry in the tables.
Claims32
A lookup table addressing system having a set of lookup tables in an external memory comprising:
- a data address generator including an input register for receiving a data word from a compute unit, the data word comprising a plurality of sections, each section comprising a reference to an entry in a table in the set of lookup tables and at least one deposit-increment index register having a table base field for identifying a location of the set of lookup tables in said external memory, a table index field identifying a location of a specific table in the set of lookup tables, and a displacement field for identifying a location of a specific entry in the specific table,
- said data address generator configured to deposit a section of the plurality of sections of said data word into said displacement field to access a partial result corresponding to said data word section before incrementing said table index field and depositing remaining sections of said data word to retrieve partial results corresponding to the remaining sections of said data word for each table in the set of lookup tables.
A lookup table addressing method for servicing a set of lookup tables in an external memory comprising:
- transferring a data word from a compute unit to an input register in a data address generator, the data word comprising a plurality of sections, each section comprising a reference to an entry in a table in the set of lookup tables;
- providing in at least one index register in the data address generator a table base field for identifying a location of the set of lookup tables in said external memory, a table index field identifying a location of a specific table in the set of lookup tables, and a displacement field for identifying a location of a specific entry in the specific table;
- depositing a section of the plurality of sections of the data word into the displacement field in said index register for identifying a location of a partial result corresponding to said data word section;
- and incrementing said table index field and depositing remaining sections of said data word to retrieve partial results corresponding to said remaining sections of said data word for each table in the set of lookup tables.
Dependencies are inferred from the claim text.