1. A method of operating a pipeline, the method comprising: initiating execution of a first instruction in parallel with a second instruction in a processor, wherein the first instruction is a one cycle execution instruction and the second instruction is a two cycle execution instruction; receiving a notification of an interrupt in the processor before completing the execution of the first instruction and before completing the execution of the second instruction; completing the execution of the first instruction and saving a first execution result in a target register specified by the first instruction; completing the execution of the second instruction and saving a second execution result in an interrupt forwarding register in response to the notification without saving the second execution result in a target register specified by the second instruction; and restoring the second execution result from the interrupt forwarding register to the target register specified by the second instruction on a return from interrupt.