Fujitsu Corporation

Fujitsu Microelectronics Limited

Akira Nodomi

Yoshimasa Takebe

Tatsumi Nakada

Hideki Sakata

Mitsuaki Hino

Eiki Ito

A memory cache device in which a storage area used for a memory data protection function is effectively used at the time of not using the memory data protection function. A mode selection signal makes ECC code sections for storing an ECC code function as a storage area for storing ECC codes used for performing error detection or error correction on data stored in data RAMs at the time the memory data protection function is enabled and as a way added to the data RAMs at the time the memory data protection function is disabled.

Cache memory device, semiconductor integrated circuit, and cache control method

A cache system includes a processing device operative to access a main memory device, a primary cache coupled to the processing device and accessible from the processing device at faster speed than the main memory device, and a secondary cache coupled to the processing device via the primary cache and accessible from the processing device at faster speed than the main memory device, wherein the primary and secondary caches are configured such that first data is stored as a data entry in each of the primary and secondary caches when the first data is read from the main memory device in response to access from the processing device, and such that second data in the secondary cache is invalidated without invalidating the second data in the primary cache when a need arises to invalidate the second data in the secondary cache in response to access from the processing device.

Non-inclusive cache system with simple control operation

A memory device that can handle various transmission-source devices and transmission-destination devices without modifying the hardware configuration. The memory device is used to transmit and receive data, and includes a data buffer for storing data output from a data-transmission source and outputting the data to a data-transmission destination serving as the data output destination; a transmission-source address converter for performing arrangement processing on the data output from the data-transmission source when the data-transmission source is a device that passively outputs data; and a transmission-destination address converter for performing arrangement processing on the data to be input to the data-transmission destination when the data-transmission destination is a device to which data is passively input.

Memory device

A cache control method controls data sharing conditions in a processor system having multi-level caches that are in an inclusion relationship. The cache control method indexes an upper level cache by a real address and indexes a lower level cache by a virtual address, and prevents a real address that is referred by a plurality of different virtual addresses from being registered a plurality of times within the same cache. A plurality of virtual addresses are registrable within the upper level cache, so as to relax the data sharing conditions.

Growing community of inventors

Kawasaki, Japan

Akira Nodomi