In one embodiment, a system includes a bus interface including a first processor, an indirect address storage storing a number of indirect addresses, and a direct address storage storing a number of direct addresses. The system also includes a number of devices connected to the bus interface and configured to analyze data. Each device of the number of devices includes a state machine engine. The bus interface is configured to receive a command from a second processor and to transmit an address for loading into the state machine engine of at least one device of the number of devices. The address includes a first address from the number of indirect addresses or a second address from the number of direct addresses.

A direct memory access (DMA) transmission control method and apparatus, where the method includes selecting a target channel for the target DMA task according to a priority corresponding to the target DMA task when a DMA transmission request for transmitting data of a target DMA task is received, querying a task type and a priority of another DMA task that has occupied a channel and a task type of the target DMA task when the other DMA task exists on the DMA channel, comparing the task type and the priority of the other DMA task that has occupied the channel with the task type and the priority of the target DMA task, and controlling data transmission on the DMA channel according to a comparison result. Hence, the urgent DMA task can be preferentially processed.

A processor that includes a memory tagging extension (MTE) provides default tag bits employed when external devices, which are not compliant with MTE, access the memory circuit (e.g., employing direct memory access (DMA)). The default tag bits are stored as first tag bits with the data in memory. The processing circuit can include a mode indicator indicating whether default tag bits are employed. In a first mode, in which the default tag bits are not employed, an exception signal may be immediately generated in response to a mismatch between the first tag bits and second tag bits in the memory instruction. In a second mode, in response to a mismatch, the first tag bits are 10 further compared to the default tag bits and an error may be generated in response to a mismatch between the first tag bits and the default tag bits.

In one example, an apparatus comprises: a direct memory access (DMA) descriptor queue that stores DMA descriptors, each DMA descriptor including an indirect address; an address translation table that stores an address mapping between indirect addresses and physical addresses; and a DMA engine configured to: fetch a DMA descriptor from the DMA descriptor queue to the address translation table to translate a first indirect address of the DMA descriptor to a first physical address based on the address mapping, and perform a DMA operation based on executing the DMA descriptor to transfer data to or from the first physical address.