US Patent 7454574 Pre-fetch control method

A pre-fetch control method comprises the following steps. First, after a data request for M-bytes request data sent from a cache controller is received, a determination is made on whether the M-bytes request data are found in the pre-fetch buffer. Then, a further determination is made on whether a combined access control is enabled if the M-bytes request data are not found in the pre-fetch buffer. If the combined access is not enabled, a data request for the M-bytes request data is sent out to an external unit. If the combined access control is enabled, a data request for the M-bytes request data and n*M-bytes extra data is sent out to an external unit. The n*M-bytes extra data is stored in the pre-fetch buffer.