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:
Sep. 05, 1995
Filed:
Dec. 08, 1993
Ruby B Lee, Los Altos, CA (US);
Joel D Lamb, Fort Collins, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A computer system provides handling of positive and negative overflow. A first arithmetic operation is performed on a first n-bit unsigned binary operand and a second n-bit signed binary operand to produce an n-bit unsigned binary result. Overflow detection logic circuitry within the arithmetic logic unit detects positive overflow or negative overflow resulting from the arithmetic operation. When there is a positive overflow, saturation logic replaces the output of the two's complement adder with a value of 2.sup.n-1. When there is a negative overflow, the saturation logic replaces the output of the two's complement adder with a value of 0. In an alternate embodiment, a first arithmetic operation is performed on a first n-bit signed binary operand and a second n-bit signed binary operand to produce an n-bit positive signed binary result. For example the arithmetic operation is an addition or subtraction performed by a two's complement adder. In the alternate embodiment, overflow detection logic circuitry within the arithmetic logic unit detects positive overflow or negative overflow resulting from the arithmetic operation. When there is a positive overflow, saturation logic replaces the output of the two's complement adder with a value of 2.sup.n-1 -1. When there is a negative overflow, the saturation logic replaces the output of the two's complement adder with a value of 0.