Patent ID: 7743218

Claim:
A method of data processing in a cache coherent data processing system including at least first and second coherency domains, said method comprising: in a first cache memory within said first coherency domain of said data processing system, setting a coherency state field associated with a storage location and an address tag to a first data-invalid coherency state that indicates that said address tag is valid and that said storage location does not contain valid data; and in response to snooping an exclusive access operation, said exclusive access operation specifying a target address matching said address tag and indicating a relative domain location of a requestor that initiated said exclusive access operation, said first cache memory updating said coherency state field from said first data-invalid coherency state to a second data-invalid coherency state that indicates that said address tag is valid, that said storage location does not contain valid data, and whether a target memory block associated with said address tag is cached within said first coherency domain upon successful completion of said exclusive access operation based upon said relative domain location of said requestor.