Techniques for the design and use of a digital signal processor, including (but not limited to) for processing transmissions in a communications (e.g., CDMA) system. Stuffing instructions in a processing pipeline of a multi-threaded digital signal processor provides for operating a core processor process and a debugging process within a debugging mechanism. Writing a stuff instruction into a debugging process registry and a stuff command in a debugging process command register provides for identifying a predetermined thread of the multi-threaded digital signal processor in which to execute the stuff instruction. The instruction stuffing process issues a debugging process control resume command during a predetermined stage of executing on the predetermined thread and directs the core processor to perform the stuff instruction during the debugging process. The core processor may then execute the stuffed instruction in association with the core processor process and the debugging process.