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:
Apr. 01, 2008
Filed:
Apr. 06, 2001
Alasdair Rawsthorne, Manchester, GB;
John H. Sandham, Manchester, GB;
Jason Souloglou, Manchester, GB;
Alasdair Rawsthorne, Manchester, GB;
John H. Sandham, Manchester, GB;
Jason Souloglou, Manchester, GB;
Transitive Limited, Manchester, GB;
Abstract
A method of handling exceptions for use in an emulator () performing program code conversion. Registers (X) of a subject machine () being emulated () are represented by a pair of abstract registers (X,X) on the target machine (), suitably using memory locations of the target machine and/or any available target registers. One of the pair (e.g., Reg X) holds a definitive value at entry into a section () of subject code () while the other (e.g., Reg X) holds a speculative value which is updated during translation and execution of that section of code. Exceptions are handled by recovering the conditions of the virtual subject machine () upon entry into the section of subject code () using the definitive version of each abstract register (i.e., Reg X). Advantageously, the function of the pair of registers (X,X) is alternated upon successful completion of each section of subject code () such that a definitive version of each register is always available for exception handling while avoiding time consuming copy and storing operations.