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.

Date of Patent:
Mar. 19, 1996

Filed:

Jul. 01, 1994
Applicant:
Inventors:

George M Uhler, Marlborough, MA (US);

John F Brown, III, Northborough, MA (US);

Assignee:

Digital Equipment Corporation, Maynard, MA (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
395375 ; 395800 ; 364D / ; 3649462 ; 3649466 ; 364955 ; 3649551 ; 3649553 ; 3649556 ; 3649577 ; 364957 ; 3649655 ; 36496422 ;
Abstract

A method of specifying the operands for a microcoded CPU employs a combination of a set of microinstruction routines for generic operand modes, along with hardware primitives for selecting various specific types of operand treatment. Decoding of a machine-level instruction produces an entry point for the microstore, selecting one of the set of generic operand modes. Also, decoding of the instruction produces control bits that are used directly to select the specific operand type or used by the hardware primitives. In this way, branching is avoided in the microinstruction sequences used for operand specifying, but yet the amount of microcode needed is a minimum.


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