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. 22, 2000
Filed:
Feb. 20, 1998
David C Johnson, Roseville, MN (US);
John S Kuslak, Blaine, MN (US);
Gary J Lucas, Pine Springs, MN (US);
Unisys Corporation, Blue Bell, PA (US);
Abstract
A method and apparatus for reducing processor response time to selected transfer instructions in an multi-instruction processor. The response time is shortened by using a fast path to generate addresses for selected transfer instructions. In this fast path a base address, retained in a register from a previous instruction, is summed with an offset from the current instruction to obtain an absolute address for memory accessing. Before the fast path is entered determinations are made whether the instruction is a particular transfer instruction of a particular class and subclass, and whether the base address is different than the base address for the previous instruction. Even through the fast path is entered the usual absolute address generator path is also entered where the instruction is subjected to both high and low limit tests. If the high and low limit test determine a different base is to be used, the absolute address from the main address generator is used, instead of the absolute address from the LXJ fast path, and the system is restored to the conditions that would have prevailed if the fast path had not been entered.