Browse Prior Art Database

Control Processor Intercept to Perform External Functions

IP.com Disclosure Number: IPCOM000037694D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Curlee, TO: AUTHOR [+5]

Abstract

A Service Processor may require the use of the Central Processor (CP) at times to perform micro-assist functions such as move storage. To do this operation, the CP must be stopped from doing its main line function in such a way as to be transparent to other elements of the system. To do this, the Service Processor sets a flag for CP microcode to test and signals the CP microcode to check this flag. This flag also signals CP's to loop on any requests they may issue while the flag is set. If the CP was stopped, the CP remains in the stopped state and the flag is set to disable other processors from starting it. If the CP was running, the receiving CP will honor all higher level interrupts before entering the paused state.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Control Processor Intercept to Perform External Functions

A Service Processor may require the use of the Central Processor (CP) at times to perform micro-assist functions such as move storage. To do this operation, the CP must be stopped from doing its main line function in such a way as to be transparent to other elements of the system. To do this, the Service Processor sets a flag for CP microcode to test and signals the CP microcode to check this flag. This flag also signals CP's to loop on any requests they may issue while the flag is set. If the CP was stopped, the CP remains in the stopped state and the flag is set to disable other processors from starting it. If the CP was running, the receiving CP will honor all higher level interrupts before entering the paused state. Upon entering the paused state, another flag will be set to indicate that this paused state had been entered from the operating state. After completion of the task for the Service Processor, the CP is removed from the paused state by a microcode command. The microcode will remove the paused state bits and continue to service requests, if it was paused while in the operating state. If the CP was stopped, the Service Processor removes the flag such that the CP remains in the stopped state but is enabled to be started by other CP's.

Disclosed anonymously.

1