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. 03, 2002
Filed:
Jul. 08, 1999
Susan Elizabeth Eisen, Austin, TX (US);
James Edward Phillips, Round Rock, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for wrap detection in a microprocessor system, the system including a plurality of rename buffers. The method includes performing a two's complement subtraction of a completion pointer from a target pointer, wherein a carry out results from the subtraction. The method further includes comparing the carryout and a virtual bit associated with a location to produce a result. The result is compared to the most significant bit of the target pointer and if there is a match between the most significant bit of the second pointer and the result, an indication is made that the instruction may issue. A system for utilizing the above method of wrap detection includes a means for performing a two's complement subtraction of a completion pointer from a target pointer, wherein a carry out results from the two's complement subtraction. The system further includes a means for performing an exclusive OR operation using the carry out and a virtual bit associated with a highest rename buffer within the plurality of rename buffers to form a result. An additional means for performing an exclusive OR operation is provided to compare the result with a most significant bit of the target pointer. Finally, an indicating means is provided to indicate a match between the most significant bit of the target pointer and the result, and therefore whether an instruction can be issued.