Data processing device with direct memory access function processed as an micro-code vectored interrupt

Claim 1

A data processing device allowing a direct memory-access operation to be performed between a read/write memory and an I/O interface, said data processing device comprising: interrupt detecting means for detecting an interrupt signal and for generating a vector corresponding to the detected interrupt signal; control signal generating means for generating, in response to said vector, a control signal indicating whether said interrupt signal is a normal interrupt signal or a direct memory-access interrupt signal; logical operation processing means, having a ROM storing micro-code instructions for executing a normal operation, a normal interrupt operation, and a direct memory-access operation, for sequentially reading out the micro-code instructions in order to control the execution of the normal operation and the normal interrupt operation, and for sequentially reading out the micro-code instructions in order to control the execution of the direct memory access operation when a control signal is generated by said control signal generating means in accordance with the interrupt signal requesting the direct memory access operation; and parameter memory means for, upon the execution of said direct memory-access operation, storing parameters for use by said logical operation processing means, for reading said parameters responsive to said vector, and for supplying said parameters to said logical operation processing means.