Saving return state data to a stack corresponding to a different mode of operation to the current mode enabling reduced interrupt latency

摘要

The present invention provides a data processing apparatus (figure 6) and method for saving return state. The data processing apparatus comprises a processing unit for executing data processing instructions, the processing unit having a plurality of modes of operation, with each mode of operation having a corresponding stack for storing data associated with that mode. The processing unit is responsive to a return state data processing instruction to write return state data of the processing unit from its current mode of operation to a stack corresponding to a different mode of operation to the current mode of operation. This approach reduces code size and improves interrupt latency.