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:
Aug. 15, 1989
Filed:
Jun. 19, 1987
Paul E Gronowski, Leominster, MA (US);
Victor Peng, Shrewsbury, MA (US);
Nachum M Gavrielov, Ashland, MA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
The arithmetic operations performed for floating point format numbers involve procedures having a multiplicity of major steps. In the performance of the effective subtraction operation, the determination of absolute value of the difference between the operand exponent arguments must be obtained in order to determine the correct procedure. In the present invention, a difference between a subset of the operand exponent arguments is calculated and the result of this calculation is used to anticipate the correct procedure. By careful selection of the anticipated correct procedure, when the selection is erroneous, the correct result is immediately available. The availabilty of the correct result is achieved by selecting the subset of operand exponent arguments so that, in the event that the result is erroneous, the correct difference is such that the associated operand fraction (i.e., to be shifted by the amount of the difference) is shifted completely out of the operand fraction field (stored in a register).