1. A processor comprising: a plurality of cores including a first core and a second core; a cache directory to store information indicating whether particular data is stored in one or more caches that are shared by the plurality of cores, the cache directory including a directory entry structure associated with each entry in the cache directory, the directory entry structure including a first field to indicate when the first core has copied the particular data to modify the particular data and a second field to indicate whether a copy of the particular data in a shared memory has been modified.