Data processing: structural design – modeling – simulation – and em – Emulation – In-circuit emulator
Reexamination Certificate
1998-10-05
2001-02-06
Teska, Kevin J. (Department: 2763)
Data processing: structural design, modeling, simulation, and em
Emulation
In-circuit emulator
C703S026000
Reexamination Certificate
active
06185523
ABSTRACT:
TECHNICAL FIELD
The present invention relates in general to data processing systems, and in particular, to an emulation of a computer system interrupt.
BACKGROUND INFORMATION
Computer system interrupts are a computer system microprocessor's means of communicating with other elements that make up a computer system. In general, computer system interrupts have been passed directly to the computer system microprocessor through the interrupt terminals of the microprocessor. The interrupt causes the microprocessor to suspend its current operations, save the status of its work, and transfer control to a special routine (known as an interrupt handler) that causes a particular set of instruction to be carried out. Interrupts have been generated for many reasons, ranging from normal to highly abnormal. These can include service requests from various hardware devices, errors in processing, program attempts to cause the computer system to do functions it is not capable of performing, and imminent failure of some vital component.
Nevertheless, only a limited number of hardwire interrupts—interrupts physically connected to a microprocessor interrupt terminal through control circuitry—could be accommodated by a processor, or they could not be implemented due to the complexity of a computer system's architecture.
Accordingly, a need exits for emulating a hardwired interrupt to achieve the same computer system effect on the system hardware, without having a hardwired interrupt connection to a microprocessor interrupt terminal.
BRIEF SUMMARY OF THE INVENTION
Accordingly, provided is an apparatus and method for generating a computer system interrupt emulation having the effect of a hardwired interrupt. A service processor with a test circuit interface can be coupled to an integrated circuit, which has a test circuit with access to a register of the integrated circuit. A program, executable by the service processor, responds to an interrupt request by instructing the service processor to save a system state of the integrated circuit and to set a system state of the integrated circuit. The method for emulating an interrupt of an integrated circuit provides for receiving an interrupt request. A register of an integrated circuit is then accessed through a test circuit of the integrated circuit. The contents of the register are saved to a storage location, and the register is then set to a state responsive to the interrupt request. The interrupt request may be made locally or remotely.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
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Itskin Randall Clay
Linam Stephen Dale
Patel Maulin Ishwarbhai
Frejd Russell W.
International Business Machines - Corporation
Kordzik Kelly K.
Leeuwen Leslie A. Van
Teska Kevin J.
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