1. A method for performing background processing in a multithread digital signal processor comprising a plurality of processing threads, said method comprising the steps of: forming a background thread interrupt as one of a plurality of interrupt types, said thread interrupt for initiating a background process using on of a plurality of processing threads of a multithread digital signal processor; storing said background thread interrupt in a interrupt register; forming a background processing mask for associating with a processing thread of said multithread digital signal processor; associating said background processing mask with at least a subset of said plurality of processing threads; sensing the presence of a predetermined event in one of said plurality of processing threads during multithread processing of said digital signal processor; issuing said background thread interrupt from said interrupt register in response to said predetermined event; and initiating background processing using a subset of said plurality of processing threads having an associated background process mask.