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:
May. 05, 1998
Filed:
Mar. 31, 1997
Charles Franklin Webb, Poughkeepsie, NY (US);
Mark Steven Farrell, Pleasant Valley, NY (US);
Mark Anthony Check, Hopewell Junction, NY (US);
John Stephen Liptay, Rhinebeck, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A special Program Status Word (PSW) millicode routine, tests the validity of the PSW with three simple millicode instructions. Testing for access exceptions is executed by a special millicode instruction 'Load With Access Test', which explicitly detects access exceptions for storage operands while retaining control in the current millicode routine. A Translate and Test (TRT) routine uses a table of 256 bytes to translate a string of bytes. Each string is used as an index into the table, and the selected table byte is fetched. For Translate and Test, the selected bytes are tested, and the first non-zero table byte selected is returned to the program in a general register along with the address of the string byte which selected it; translate and test also sets the condition code, and does not update storage. To provide reasonable performance on Translate and Translate and Test, while maintaining flexibility and simplicity of a millicoded design, a millicode instruction Translate Fetch (TRFET) is provided specifically for use in execution of the Translate and Translate and Test instructions. This Translate Fetch millicode instruction uses an RX format, but modifies the interpretation of the certain fields.