Execution circuits using discardable state

Abstract

There is provided execution circuitry. Storage circuitry retains a stored state of the execution circuitry. Operation receiving circuitry receives, from issue circuitry, an operation signal corresponding to an operation to be performed that accesses the stored state of the execution circuitry from the storage circuitry. Functional circuitry seeks to perform the operation in response to the operation signal by accessing the stored state of the execution circuitry from the storage circuitry. Delete request receiving circuitry receives a deletion signal and in response to the deletion signal, deletes the stored state of the execution circuitry from the storage circuitry. State loss indicating circuitry responds to the operation signal when the stored state of the execution circuitry is not present and is required for the operation by indicating an error. In addition, there is provided a data processing apparatus comprising issue circuitry to issue an operation to execution circuitry. The execution circuitry stores a stored state that is accessed during performance of the operation and error detecting circuitry detects an indication of an error from the execution circuitry that the stored state is required for performance of the operation and that the stored state has been deleted.