DATA PROCESSING SYSTEM, AND DATA PROCESSING METHOD

According to a data processing apparatus and a data processing method of the present invention, supply of clocks is controlled according to various kinds of processing commands which are issued from a command issuing source and, when a first buffer memory underflows, a data transfer request is made without terminating a data processing command, and data processing is resumed at the completion of a data transfer command. Therefore, supply of clocks can be stopped when data are not transferred and when data are not processed, whereby power consumption can be reduced. Further, when the first buffer memory underflows, it is not necessary for the command issuing source to issue a data processing command again, whereby the number of commands to be issued can be reduced.