Patent decision

BL number
Concerning rights in
Hearing Officer
Mr P Slater
Decision date
1 February 2010
Person(s) or Company(s) involved
ARM Limited
Provisions discussed
PA 1977 Section 1(2)
Excluded fields (refused)
Related Decisions


The invention relates to the simulation and testing of programmable devices and associated programs designed to run thereon. Modelling the device and associated programs in this way helps to identify potential problems early on in the development life-cycle so that they can be overcome relatively easily and inexpensively by modification of the original design. Being able to design and simulate the programs in parallel with the development of the hardware upon which they will be executed also reduces the overall development time and makes the process more efficient.

The applicant itself produces a wide range of modelling tools which enable users to produce so called “cycle accurate” models for simulating microprocessors on a general purpose computer. These models can be used, not only to model the microprocessor itself, but also the program code designed to run thereon. However, problems arise when the simulated model of the microprocessor and/or the program code being subject to simulated execution contain “bugs” which need to be identified and fixed. Difficulty arises in that when the simulation is being run and produces unexpected results, it is often difficult to locate whether the problem lies in the simulated model of the hardware or within the program code. The invention provides a new technique whereby the behaviour of the simulated device and the program code can be tracked simultaneously and the location of any bugs can be more readily identified. This is achieved by an arrangement in which the so called “host debugger” and “target device debugger” are synchronised, and a “debug interface” is provided for enabling access to stored information regarding the state of resources being used by the host simulation and the state of the device being simulated.

The hearing officer considered the four-step test in Aerotel/Macrossan in the light of the Symbian judgment, and found the contribution to relate to computer program for locating bugs in simulation software. The Hearing Officer could find no technical contribution and so refused the application under Section 18(3).

Full decision O/036/10 PDF document130Kb