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Hardware Monitor of Selected Monitor Call Hooks

IP.com Disclosure Number: IPCOM000084118D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hildebrand, DB: AUTHOR

Abstract

There are two concepts in this description. The first concerns an extension of the way interrupts are controlled. The usual way of permitting an interrupt is by the use of a mask in a control register. Monitor Call (MC) instruction interrupts are controlled this way in IBM S370.

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Hardware Monitor of Selected Monitor Call Hooks

There are two concepts in this description. The first concerns an extension of the way interrupts are controlled. The usual way of permitting an interrupt is by the use of a mask in a control register. Monitor Call (MC) instruction interrupts are controlled this way in IBM S370.

Some parts of an operating system cannot tolerate an interrupt, in particular, the code that processes interrupts. As this is a desirable location to place MC instructions for hardware monitoring, it is necessary to inhibit any interrupts that could occur for a MC instruction in a particular location in the system, while permitting others to occur under control of the mask in a control register. This is accomplished with this method by defining a bit in the MC instruction, which inhibits an otherwise enabled interrupt for the instruction in which it appears.

The second concept concerns the modification of control store by an instruction to change the behavior of that instruction class. In the implementation of this method, the modification concerns the tables used to control the action on the hardware interface used for measurement whereby a given type of MC instruction is executed. In essence, this extension of the MC instruction enables it to transfer data to and from control store, which controls the action taken for further executions of the instruction.

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