Abstract: A virtual FIFO automatic data transfer mechanism. A processor unit may allocate memory space within system memory for a data transfer operation. The processing unit may also program both a source device and a target device to perform the data transfer operation. After the programming, the source and target devices perform the data transfer operation without intervention by the processing unit until completion. The source device may store data into the allocated memory space, and indicate to the target device when it has stored a predetermined number of data bytes into the allocated memory space. In response to receiving the notification message, the target device may read the stored data from the allocated memory space, and indicate to the source device when the target device has read a predetermined number of data bytes from the allocated memory space.