摘要 |
One embodiment of the present invention provides a system which creates multiple checkpoints in a processor that supports speculative-execution. The system starts by issuing instructions for execution in program order during execution of a program in a normal-execution mode. Upon encountering a launch condition during an instruction which causes a processor to enter execute-ahead mode, the system performs an initial checkpoint and commences execution of instructions in execute-ahead mode. Upon encountering a predefined condition during execute-ahead mode, the system generates an additional checkpoint and continues to execute instructions in execute-ahead mode. Generating the additional checkpoint allows the processor to return to the additional checkpoint, instead of the previous checkpoint, if the processor subsequently encounters a condition that requires the processor to return to a checkpoint.
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