Patent ID: 7310800

Claim:
In a processing system, a method of providing a patch to replace a selected existing code function in a ROM or adding a new code function, the method comprising the steps of: determining an existing ROM address for the selected existing code function or a desired ROM address for the new code function; installing a loader module in a first location in a first memory; installing the patch or the new code function in a second location in the first memory, the patch comprising a replacement code function; pre-loading the patch or the new code function by transferring the patch or the new code function in response to instructions in the loader module before the patch or the new code is required by the processor to a cache, the cache being configured to cache instructions from the ROM and from the first memory, wherein the cache is memory-mapped to the existing ROM address for the selected code function or the desired ROM address for the new code function; and when requiring instructions located at the existing ROM address or the desired ROM address, fetching the patch from the cache rather than the ROM, or fetching the new code function from the cache.