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:
Jul. 25, 1989

Filed:

Jun. 19, 1987
Applicant:
Inventors:

Vijay Maheshwari, Northboro, MA (US);

Sridhar Samudrala, North Grafton, MA (US);

Nachum M Gavrielov, Ashland, MA (US);

Assignee:

Digital Equipment Corporation, Maynard, MA (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
364748 ;
Abstract

The arithmetic operations performed for floating point format numbers involve procedures having a multiplicity of major steps. The effective subtraction operation can be accelerated by using two methods of execution depending on whether the absolute value of the difference between the arguments of the exponents, ABS{DELTA(E)} is .ltoreq.1 or >1. The procedure for ABS{DELTA(E)}.ltoreq.1 requires more major process steps than the situation where ABS{DELTA(E)}.ltoreq.1. To accelerate only the procedure having more major process steps, the two least significant bits of both exponent arguments are examined and based on the examination, the lengthier procedure can be initiated in parallel with the process step determining the value of ABS{DELTA(E)}. When the lengthier procedure is determined to be inappropriate based on the determined value, the results of the lengthier process can be discarded. Otherwise, the lengthier process, already in progress, is continued.


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