Fujitsu Corporation

Hitoshi Yoda

Yasuhiro Yamazaki

Atsuhiro Suga

Hiroshi Okano

Hiroyuki Utsumi

Teruhiko Kamigata

Hideo Miyake

Yoshio Hirose

Taizo Sato

Yasuki Nakamura

Yoshimasa Takebe

Taizoh Satoh

Shin-ichiro Tago

An information processing device reads, buffers, decodes and executes instructions from an instruction store portion by pipeline processing includes: an instruction reading request portion which assigns a read address to the instruction store portion, an instruction buffering portion which includes a plurality of instruction buffers which buffer an instruction sequence read from the instruction store portion; an instruction execution unit which decodes and executes instructions buffered by the instruction buffering portion. A branching instruction detection portion detects a branching instruction in the instruction sequence read from the instruction store portion. A branch target address information buffering portion includes a plurality of branch target address information buffers which, when the branching instruction detection portion has detected a branching instruction, buffer the branch target address information for generating the branch target address of the branching instruction.

Processing device for buffering sequential and target sequences and target address information for multiple branch instructions

In a cache memory control method and computer of the present invention, a cache memory is connected to a main memory and divided into a plurality of cache blocks, and a lock/unlock signal is supplied to the cache memory to either set a replace-inhibition state of at least one of the cache blocks in which replacing at least one of the cache blocks to the main memory is inhibited, or reset the replace-inhibition state of at least one of the cache clocks such that replacing at least one of the cache block to the main memory is allowed. Either reading or writing of the main memory is performed by using the remaining cache blocks of the cache memory, other than the at least one of the cache blocks, such that, when the replace-inhibition state is set by the lock/unlock signal, replacing the at least one of the cache blocks to the main memory is inhibited during the reading or writing of the main memory.

Method of Controlling and addressing a cache memory which acts as a random address memory to increase an access speed to a main memory

A microprocessor includes a register and a comparator. The register stores an address area, the address area requiring a guarantee of an access order. The comparator compares an address of the address area held in said register with an address of an address area indicated in an access request from CPU, and outputs a signal to execute an access request succeeding the access request from the CPU after executing an access request preceding the access request from the CPU when the address area indicated in the access request from the CPU matches the address area held in said register.

Microprocessor executing a program to guarantee an access order

The present invention provides a data processor including an instruction cache that can operate at low power consumption, avoiding useless power consumption. The data processor includes a plurality of cache memory units, wherein only a cache memory unit that stores a demanded instruction is enabled, while other memory units are disabled.

Data processor having instruction cache with low power consumption

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Kawasaki, Japan

Hitoshi Yoda