6 results about "Direct memory access" patented technology

Embodiments of the invention may be used to manage message queues in a parallel computing environment to prevent message queue deadlock. A direct memory access controller of a compute node may determine when a messaging queue is full. In response, the DMA may generate an interrupt. An interrupt handler may stop the DMA and swap all descriptors from the full messaging queue into a larger queue (or enlarge the original queue). The interrupt handler then restarts the DMA. Alternatively, the interrupt handler stops the DMA, allocates a memory block to hold queue data, and then moves descriptors from the full messaging queue into the allocated memory block. The interrupt handler then restarts the DMA. During a normal messaging advance cycle, a messaging manager attempts to inject the descriptors in the memory block into other messaging queues until the descriptors have all been processed.

The invention provides a file writing-in method of a SD (Secure Digital) card. The file writing-in process relates to a one-step DMA (Direct Memory Access) transmission process of wiring file data into a continuous physical cluster of the SD card from a discontinuous memory address. The method comprises the steps of: configuring first file transmission information, wherein the first file transmission information comprises initial addresses of multiple sections of file data in the memory and the information of the continuous physical cluster in the SD card; and sequentially reading data with corresponding length from the multiple sections of initial addresses of the memory, and continuously writing the data into the continuous physical cluster of the SD card. The invention can improve the direct memory access speed of the SD card and reduce the resource occupation of CPU (Central Processing Unit).

The invention discloses a condition access chip of a digital television and a realization method of condition access. The condition access chip comprises a central processing unit, a transmission flow processor, a nonvolatile memory and a control word decryption module; a DMA (Direct Memory Access) controller is used for controlling the control word decryption module to finish decryption operation on a control word according to a task chain table which is stored in the nonvolatile memory; and a storage protection unit is used for carrying out safety configuration according to configuration information obtained by the DMA controller from the nonvolatile memory, and then protecting a bus address interval of the chip through constructing a safety island. According to the invention, through constructing the safety island and configuring the task chain table of the DMA controller, an attacker cannot execute an illegal task chain table by the DMA controller to attack the condition access chip, thereby improving the safety performance of the condition access of the digital television.

The invention discloses a ping-pong RAM-based strip array convolution module and an operation method thereof. The convolution module comprises a direct memory access module DMA, a DMA controller, a data distribution module, a ping-pong RAM, an RAM reading module, a strip array module, a block accumulation module and a register module. The DMA controller is used for controlling DMA to read data from a memory, and the data comprises a feature and a weight; the characteristic feature and the weight weight weight of the data are separted through a data distribution module, and then the data is stored into a ping-pong RAM; the RAM reading module is used for reading features and weights from the ping-pong RAM and sending the features and the weights to the strip array module for operation processing, and an operation result is output through the block accumulation module; and the register module is used for receiving a register configured by the central processing unit to control the convolution module to operate. According to the invention, the utilization rate of the multiplier can be improved, and convolution kernels of different sizes can be compatible.