US 5,510,973 AGranted

Buffer storage control system

AssigneeFujitsu Limited

InventorTetsuya Morioka

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Abstract

In a buffer storage control system for controlling a buffer storage based on a part of a page address of a logical address and a part of a byte index of the logical address which is used as a line address, the system includes: a tag portion TAG1 (13, 17) provided in a plurality of pipe lines (IF, OP) of a central processing unit CPU (1) to retrieve a hit/mis-hit of data based on a part of the page address of the logical address and a part of the byte address of the logical address which is used as the basic line address; a data portion DATA (14, 18) for holding data when retrieving the tag portion TAG1 by the basic line address and when the data is hit; and a tag portion TAG2 (21, 22) provided in a MCU, when the data is mis-hit by using the basic line address, to retrieve the hit/mis-hit of data by using a synonymic line address which is obtained by changing a variable portion of the basic line address; wherein, in a data access, the tag portion TAG1 is retrieved by using only the basic line address, when the data is hit using the tag portion TAG1, the data portion DATA is accessed, on the other hand, when the data is mis-hit using tap portion TAG1, the tag TAG2 is retrieved by using the basic line address and the synonymic line address, further, when the data is hit using tap portion TAG2, the data portion DATA is invalidated, a move-out operation is invalidated, and a move-in operation is validated.

A data processing apparatus formed by a plurality of central processing units, a main storage unit, and a main storage control unit provided between the central processing units and the main storage unit, the apparatus comprising:

each central processing unit including a) a calculation control unit for generating an instruction fetch request and an operand access request and for receiving an instruction fetch data, b) a calculation execution unit for generating a store data and for receiving an operand fetch data, and c) a storage control unit for receiving the instruction fetch request and the operand access request,
the storage control unit including an instruction access pipe line for an instruction access and an operand access pipe line for an operand access,
the instruction access pipe line including a) an address conversion buffer for converting from the logical address to the absolute address to perform the fetch access for the instruction with high speed, b) a tag portion for retrieving based on the basic line address at the fetch access of the instruction and for determining a hit/mis-hit of data, and c) a buffer storage data for the instruction access to read the data when the data is hit,
the operand access pipe line including a) an address conversion buffer for converting from the logical address to the absolute address to perform the fetch access and store access of the operand, b) a tag portion for retrieving based on the basic line address at the fetch access and store access of the operand and for determining and hit/mis-hit of data, c) a buffer storage data for the operand access to read the data when the data is hit, and d) a store buffer for temporarily storing the store data, and
the main storage control unit including a) a first tag portion for the instruction access for retrieving based on the synonymic line address at the fetch access of the instruction and for determining the hit/mis-hit of the data, and b) a second tag portion for the operand access for retrieving based on the synonymic line address at the fetch access and the store access of the operand and for determining the hit/mis-hit of the data.

2 more elements

Abstract

Claims1