Abstract: A digital signal processing system for executing instructions and processing data, including a program memory which stores the instructions and a first portion of the data, a data memory which stores a second portion of the data, and a program control unit connected to the program memory for receiving a sequence of the instructions and generating control signals for executing the instructions, wherein the program control unit is programmed to fetch at least one data value from the program memory in response to at least one of the instructions. Preferably, the system also includes a memory management unit connected to the program control unit and the data memory for generating address signals in response to at least one of the control signals for use in reading data values from the data memory.

Abstract: A digital signal processing system and method for executing instructions with decode, read, execute, and write pipeline cycles. In the decode cycle, control signals are generated which determine addresses which in turn determine memory locations from which data are to be read and to which processed data are to be written. The system includes a program control unit for processing a sequence of instructions and controlling system operation, a memory, a data processing unit, and a dedicated bus for writing processed data from the data processing unit to the memory. By using a dedicated write bus, the system avoids bus contention in a five stage pipeline operation involving fetch, decode, read, execute, and write operations. A post shift unit connected along the write bus shifts data values that have been output from the data processing unit before they are written to the memory.

Abstract: A method and apparatus for implementing a discrete cosine transform (DCT) or an inverse DCT (IDCT) with a single hardware unit which applies only positive valued multiplicative coefficients and can be switched to either perform a DCT or an IDCT. The invention processes parallel input digital data signals to produce parallel output digital data signals which represent a discrete transform (either a DCT or an IDCT) of the input data. One aspect of the invention is a method and apparatus for performing discrete transforms using a multiplier which implements MSB-first, bit-serial, carry-save, multiplication of an input word by a positive fixed coefficient. In one class of embodiments, the serially received digits of the input word can take on positive values only. In other embodiments, the serially received digits of the input word can take on positive or negative values.