A processor may operate in one of a plurality of operating states. In a
Normal operating state, the processor is not involved with a memory
transaction. Upon receipt of a transaction instruction to access a memory
location, the processor transitions to a Transaction operating state. In
the Transaction operating state, the processor performs changes to a
cache line and data associated with the memory location. While in the
Transaction operating state, any changes to the data and the cache line
is not visible to other processors in the computing system. These changes
become visible upon the processor entering a Commit operating state in
response to receipt of a commit instruction. After changes become
visible, the processor returns to the Normal operating state. If an abort
event occurs prior to receipt of the commit instruction, the processor
transitions to an Abort operating state where any changes to the data and
cache line are discarded.