Information processing device comprising a read-only memory and a method for patching the read-only memory

摘要

Patching a read-only memory, including a program executable by a processor is performed with a MRAM-based CAM device connected to the address bus and comparing in the background the addresses requested by the processor with the elements of a vector of addresses. The match-in-place operation is done in parallel on all the elements of the vector and typically is performed in less than a clock cycle. If a match is found, the CAM device outputs a diversion address that's used to retrieve a substitution machine code element from a flash memory that is presented to the processor in lieu of the one addressed in the ROM. This patching scheme is totally transparent, has little overhead, and extreme granularity.