Apparatus and method for predicting target storage unit

A data processing apparatus comprises processing circuitry and a plurality of storage units. When the processing circuitry executes a data access instruction, then a storage controller identifies based on a target storage address of the data access instruction, which of the storage units includes the target storage location identified by the target storage address. Prediction circuitry is provided to predict a predicted storage unit predicted to include the target storage location, so that retrieval of the data value from the predicted storage unit can be initiated before the storage controller has identified the target storage unit. The prediction circuitry makes the prediction based on the type of the data access instruction executed by the processing circuitry.