Memory access control circuit with automatic access mode determination circuitry with read-modify-write and write-per-bit operations

U.S. Patent Number: 5394535

Abstract: A memory access control circuit determines an optimum memory access mode and performs the optimum memory access mode without requiring additional data from the data processing unit. The circuit performs a plurality of memory access operations, the number of which is larger than the number of access modes designated by the data processing unit, and decides automatically which memory access is to be performed, and independently executes the appropriate memory access. The memory access control circuit provides memory access control functions which make it particularly suited for use in a graphics display system.

Inventors: Ohuchi; Mitsurou (Tokyo, JP)

Assignee: NEC Corporation (Tokyo, JP)

Application Number: 08/068,578

Issued: 1995-02-28

Expired: 2007-02-28

Classes: 711/155

Field of search: 364/2MSFile,9MSFile 395/425

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