US Patent 7200742 System and method for creating precise exceptions

A method for creating precise exceptions including checkpointing an exception causing instruction. The checkpointing results in a current checkpointed state. The current checkpointed state is locked. It is determined if any of a plurality of registers require restoration to the current checkpointed state. One or more of the registers are restored to the current checkpointed state in response to the results of the determining indicating that the one or more registers require the restoring. The execution unit is restarted at the exception handler or the next sequential instruction dependent on whether traps are enabled for the exception.