Abstract: A data processing device is provided which has multiprocessors that can be configured on a cycle by cycle basis as loosely coupled or tightly coupled. Bit-stream Processing Unit (BPU) 110 executes instructions from ROM 112 and accesses data from RAM 111. Similarly, Arithmetic Unit (AU) 120 executes instructions from ROM 122 and accesses data from RAM 121. Both processor operate in parallel and exchange data by accessing RAM 121. AU 120 can receive an instruction directive from BPU 110 directing it to perform a selected sequence of instructions in a loosely coupled manner. AU 120 can also receive an instruction directive from BPU 110 directing that a portion of AU 120 operationally replace a portion of BPU 110 for the duration of one instruction which allows data to be passed directly between the processors in a tightly coupled manner.

Abstract: A data processing device is programmed to decode and transform a stream of data representing a plurality of subband encoded channels of audio data into one or more channels of PCM encoded data for reproduction by a speaker subsystem. An improved method for decoding and transforming utilizes downmix matrices (1021 and 1022) to form downmixed frequency domain channels in buffers (1031-1034). Only two long DCT transform operations (1041 and 1042) and two short DCT transform operations (1043 and 1044) are needed to transform the downmixed frequency domain channels into a left PCM output (1071) and a right PCM output (1072).