A data processing system includes a memory subsystem and an execution
unit, coupled to the memory subsystem, which executes store instructions
to determine target memory addresses of store operations to be performed
by the memory subsystem. The data processing system further includes a
mode field having a first setting indicating strong ordering between
store operations and a second setting indicating weak ordering between
store operations. Store operations accessing the memory subsystem are
associated with either the first setting or the second setting. The data
processing system also includes logic that, based upon settings of the
mode field, inserts a synchronizing operation between a store operation
associated with the first setting and a store operation associated with
the second setting, such that all store operations preceding the
synchronizing operation complete before store operations subsequent to
the synchronizing operation.