Hitachi, Ltd.

Hitachi Microcomputer System, Ltd.

Hitachi Information Technology Co., Ltd.

Hitachi Computer Eng. Co., Ltd.

Hiromichi Kainoh

Akira Yamaoka

Koji Kawamoto

Fujio Wakui

Takaaki Nishiyama

Tohru Hiraoka

Seiji Nagai

Kuniki Tohbaru

An address translation buffer system in which a searching time of an address translation buffer is shortened. The address translation buffer includes an address translation buffer connected to a translation table for translating a virtual address to a real address, the address translation buffer containing a plurality of columns holding a plurality of entries each having a pair of the virtual address and the real address translated based on the translation table and also having a virtual machine classification indicative of a type of the virtual address, a plurality of column control circuits for specifying columns of the address translation buffer with a combination of a lower part of the virtual address and the virtual machine classification as an entry, and circuits, in accordance with an invalidation instruction for purging one of the entries of the address translation buffer, for searching one of the columns of the address translation buffer having one of the entries of the address translation buffer coincided with the virtual machine classification entry of the invalidation instruction and for invalidating the entry including a specified field. It is unnecessary to search a group of columns having values other than the specified virtual machine classification.

Address translation buffer system and method for invalidating address

Under such a condition between outputs of AND circuits for outputting All '0' when one of zero detecting circuits of two register identifiers within an instruction register detects '0', instead of a content of a general-purpose register designated by these identifiers, and also a carry derived from a page offset corresponding to an intermediate result of an address adder, when a page address portion of a logical address is known before this logical address is defined, selecting circuits are controlled, and then the address controller is bypassed to retrieve a translation look-aside buffer, thereby defining a real address. In case that the page address portion of the logical address register is identical to the page address portion of the base register, the translation look-aside buffer is previously retrieved in accordance with either the content of the index register, or the content of the base register so that the real address can be defined.

Logical-to-real address translation based on selective use of first and

A data processing system includes a multistage pipeline arithmetic/logic operation unit for implementing an arithmetic or logic operation for sets of element data sequentially and storing operational results sequentially in a memory using a single instruction. Check information indicative of the presence or absence of a fault occurring in each stage of the pipeline operation unit is moved in synchronism with the advancement of stages of the pipeline operation unit. A request control unit for storing the operational result in the memory suppresses the storing of the operational result in the memory if check information indicates a fault of the operational result which is being stored in the memory. The request control unit issues storage requests, which are counted by a counter. The counter indicates the number of elements stored normally in the memory.

Data processing system having pipeline arithmetic/logic units

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Hadano, Japan

Hiromichi Kainoh