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:
Jan. 15, 1985
Filed:
Apr. 26, 1982
George H Bean, Hyde Park, NY (US);
Peter H Gum, Poughkeepsie, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The embodiment obtains rapid switching between system control programs (SCPs) by switching an address in a prefix register in a CPU of a MP or UP data processing system from a guest SCP's PSA (program save area) to a host SCP's PSA by fetching the host prefix value from a predetermined control block in main storage. The prefix register loading changes the control of the CPU from a preferred guest SCP to a host SCP. This SCP switching is done by hardware and/or microcode means in the CPU. It further detects preset states in the CPU that enable a rapid determination of which SCP is to handle a sensed event, permitting the guest SCP to immediately handle events predetermined to belong to the guest. This manner of CPU control obtains for a preferred guest SCP (such as MVS/370) operating under a host SCP (such as VM/370) nearly the efficiency of standalone execution on the CPU by the preferred guest SCP.