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Circular Addressing Circuitry for Accessing Computer Storage

IP.com Disclosure Number: IPCOM000088775D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Hatfield, GH: AUTHOR [+3]

Abstract

When addressing members of an array which are stored sequentially in memory, a computer program can address each member as an offset from the first member of the array, using an index register which contains the address of the first member of the array. If, however, the array is constrained to a portion of storage such that sequential values, which would normally be located past an upper bound, would "wrap around" to a lower bound and sequentially overlay the values in the lower addresses, the addressing technique indicated above would not work. The subject technique provides computer hardware which allows a computer program to address an array of data in storage as if it were sequentially stored, where, in fact, it is stored in a "circular" fashion.

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Circular Addressing Circuitry for Accessing Computer Storage

When addressing members of an array which are stored sequentially in memory, a computer program can address each member as an offset from the first member of the array, using an index register which contains the address of the first member of the array. If, however, the array is constrained to a portion of storage such that sequential values, which would normally be located past an upper bound, would "wrap around" to a lower bound and sequentially overlay the values in the lower addresses, the addressing technique indicated above would not work. The subject technique provides computer hardware which allows a computer program to address an array of data in storage as if it were sequentially stored, where, in fact, it is stored in a "circular" fashion.

In some computer applications, such as signal processing, large amounts of data are dynamically processed. In order to maintain a portion of this data for processing, it is desirable to constrain the data to a portion of storage such that the newest data overwrites the oldest data in a circular way. Accessing the "wrapped-around" data with a computer program is not straightforward, since the location of an array within the circular portion of storage may change dynamically, and its members may be noncontiguous due to the circular manner in which it is stored.

One method of circular addressing is described which addresses a "binary" portion of storage. That...