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Browse Prior Art Database

Interrupted Task Reinitialization

IP.com Disclosure Number: IPCOM000088292D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Atkins, JD: AUTHOR

Abstract

This article describes a method for providing automatic reinitialization of an interrupted program in a microprocessor operated on an interrupt basis. Information gathering tasks, such as statistical usage monitoring functions, peripheral device status and other system housekeeping chores, are often performed on a low or the lowest priority level in an interrupt-driven machine and are, consequently, often subject to interruption before completion.

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Interrupted Task Reinitialization

This article describes a method for providing automatic reinitialization of an interrupted program in a microprocessor operated on an interrupt basis. Information gathering tasks, such as statistical usage monitoring functions, peripheral device status and other system housekeeping chores, are often performed on a low or the lowest priority level in an interrupt-driven machine and are, consequently, often subject to interruption before completion.

Because of the nature of the tasks, i.e., current information gathering, it is not convenient to resume the task from the point at which it was interrupted. Instead, it is necessary to reinitialize the task and begin anew from the start. This requires either a lengthy set of checks and loop-back to the beginning in the event an interrupt is detected in the application task prodram, or specialized hardware subject to the interrupt level at which the task is perfom ed which will automatically reinitialize the task by resetting an instruction count whenever the task has been interrupted. An alternative technique utilizing dual program status word registers in a microprocessor is shown here.

The figure illustrates a general schematic flow diagram for the process of reinitializing the application task for a data gathering or other similar function, as noted above. The control program in the microprocessor 1 provides initial loadings for the interrupt request register (IRR) 2, the program status word control register 3 (PCR) and the primary and secondary PSW registers 4 and 5, respectively. In operation, when the processor has reached...