The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 1995
Filed:
Dec. 12, 1991
Chikako Ikenaga, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
Source operand data supplied from a register file are held in registers. The data of the registers and load data from a data memory are bypassed and supplied to a selection circuit. An execution stage includes an arithmetic and logic unit for performing an operation on the source operand data and a memory access stage includes an arithmetic and logic unit for performing an operation on data selected by the selection circuit. Selection of the selection circuit is controlled by data dependency between a load instruction and an operation instruction following the same. The output of the arithmetic and logic unit in the execution stage and the output of the arithmetic and logic unit in the memory access stage are selected in a selector according to a presence/absence of data dependency. Load data from the data memory is also supplied to the selector. If an operation instruction supplied following a load instruction uses load data, execution of this operation instruction in the memory access stage eliminates a pipeline stall and the need for inserting a 'NOP' instruction for pipeline stall prevention, making it possible for an operational processing unit to operate at a high speed without causing a slot in the pipeline.