Abstract: A method of transferring a block of data from a first to a second circular buffer of a computer system. The method comprises notifying the DMA controller of the source and destination addresses for the transfer, the sizes of the circular buffers, and the size of the data block to be transferred. At the DMA controller, respective base and rollover addresses of the circular buffers are identified. Data is read from the first circular buffer starting at the source address, continuing until the rollover address is reached, and continuing from said buffer base address until the end of the block is reached. Data is written to the second circular buffer starting at the destination address, continuing until the rollover address is reached, and continuing from said buffer base address until the end of the block is reached.

Abstract: A Direct Memory Access (DMA) controller 5 for transferring data from a first to a second location under the control of a processor 7, the DMA controller 5 comprising at least three ports, each port being configurable to act as an input or output port of the DMA controller 5 and to be coupled to any one of the other ports.

Abstract: A method of transferring a block of data from a first to a second circular buffer of a computer system. The method comprises notifying the DMA controller of the source and destination addresses for the transfer, the sizes of the circular buffers, and the size of the data block to be transferred. At the DMA controller, respective base and rollover addresses of the circular buffers are identified. Data is read from the first circular buffer starting at the source address, continuing until the rollover address is reached, and continuing from said buffer base address until the end of the block is reached. Data is written to the second circular buffer starting at the destination address, continuing until the rollover address is reached, and continuing from said buffer base address until the end of the block is reached.