MESSAGE HANDLING COMMUNICATION BETWEEN A SOURCE PROCESSOR CORE AND DESTINATION PROCESSOR CORES

A data processing apparatus comprises at least one source processor core, at least two destination processor cores, a message handler and a bus arrangement providing a data communication path between the source core, the destination cores and the message handler. The message handler has plurality of message-handling modules. At least one of the message-handling modules has a message receipt indicator that is modifiable by each of the destination processor cores to indicate that a message has been received at its destination. This message-handling module also has a transmission completion detector operable to detect, in dependence upon a message receipt indicator value that a message has been received by all of the at least two destination processor cores and to initiate transmission of an acknowledgement signal to the source processor core.