Patent decision

BL number
Concerning rights in
Hearing Officer
Mr S Probert
Decision date
23 September 2004
Person(s) or Company(s) involved
ARM Limited
Provisions discussed
PA 1977 Section 1(2)(c)
Excluded fields (allowed)
Related Decisions


This application concerned a simulator for simulating the operation of a pipelined microprocessor. Each stage of the pipeline is modelled by a piece of software that takes data from an input register, operates on it in such a way as to replicate the function of the hardware stage that is being modelled, and then loads the result into an output register. At the end of each simulated clock cycle, the data from each stage is transferred from each output register to the input register of the next stage ready for the next clock cycle. Thus for every stage in the pipeline, the simulator has to execute a COPY instruction in order to transfer data from each stage to the next. The invention in this case involves locating all of the input registers in one data storage area, and all of the output registers in another data storage area. Then the simulator only has to switch the two storage areas around (eg. by exchanging two pointer values) in order to effectively COPY all of the output registers to the corresponding input registers of the next stage in a single operation. The Hearing Officer concluded that this invention did involve a technical contribution not simply because it produced a faster simulator, but because the fundamental construction of the simulator had been modified. He described it as a technical improvement in the construction and operation of a simulator a 'neat' technical solution to a technical problem.

Full decision O/292/04 PDF document52Kb