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:
Dec. 09, 1986
Filed:
Nov. 14, 1983
Fredrick L Zardiackas, Sunnyvale, CA (US);
Tandem Computers Incorporated, Cupertino, CA (US);
Abstract
The disclosure relates to a re-vectoring circuit of a microprocessor system wherein pending interrupts are serviced without unnecessary microprocessor state store and restore operations associated with a return-from-interrupt instruction. At the conclusion of an interrupt service routine, an indirect jump instruction is executed through the same address location of an interrupt vector that the microprocessor indirectly jumped through when the microprocessor was initially interrupted. However, the indirect address is modified, that is, re-vectored to an indirect address within a predetermined address vector depending upon the type of a pending interrupt. The re-vectoring circuit recognizes the indirect jump address and then senses a pending interrupt if there is a pending interrupt. The re-vectoring circuit modifies the indirect address such that a jump occurs to the highest priority pending interrupt service routine. This modification of the indirect address eliminates the store and restore of the microprocessor state in between the servicing of various interrupts.