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:
Nov. 22, 1994
Filed:
Oct. 02, 1992
Compaq Computer Corporation, Houston, TX (US);
Abstract
A method and apparatus which maintains strict ordering of processor cycles to guarantee that a processor write, such as an EOI instruction, is not executed to the interrupt controller prior to the interrupt request from a requesting device being cleared at the interrupt controller, thus maintaining system integrity. Interrupt controller logic is included on each respective CPU board. The processor can access the interrupt controller over a local bus without having to access the host bus or the expansion bus and thus an interrupt controller access could be completed before a previously generated I/O cycle has completed. Therefore, the apparatus which tracks expansion bus cycles and interrupt controller accesses and maintains strict ordering of these cycles to guarantee that an interrupt request is cleared at the interrupt controller prior to execution of write operation to the interrupt controller.