A system including: a first memory including several portions of one or more pages each, said memory including first and second ports that can simultaneously access, for reading and writing respectively, two distinct pages of portions of the memory; and a control circuit capable of performing write operations to the pages of the memory, each write operation to a page of the memory requiring a reading step of a former datum on said page via the first port, and including a writing step of a new datum to the page via the second port, taking account of the former datum.