Ati International Srl

Ati Technologies Ulc

Steve C Hale

Stephen C Purcell

Parin Bhadrik Dalal

Nital P Patwa

Chad Edward Fogg

Korbin S Van Dyke

Korbin Van Dyke

An apparatus includes at least one general purpose register and at least one special purpose register and an execution unit that executes at least two instructions in parallel, to decode variable length codes, wherein each of the instructions share use of the at least one general purpose register and the at least one special purpose register. In one example, a processor stores variable length code information among a plurality of general purpose registers and generates decoded variable length code information by decoding the at least one variable length code. The processor also stores the decoded variable length code information among the plurality of general purpose registers.

Variable-length code decoder

A method that decodes serially received MPEG variable length codes by executing instructions in parallel. The method includes an execution unit which includes multiple pipelined functional units. The functional units execute at least two of the instructions in parallel. The instructions utilize and share general purpose registers. The general purpose registers store information used by at least two of the instructions.

In accordance with the present invention, an adder tree structure includes at least two adder stages. In the circuit and method according to the present invention, the first of the two adder stages generates two bits of a common weight and other more significant bits of a weight one bit more significant than the two bits of the common weight. The second of the two adder stages includes an adder that receives the more significant bits generated in the first of the two adder stages. The second adder stage also includes an AND gate which receives and logically AND's the two bits of the common weight to generate a carry-in bit for the adder in the second stage. The above adder tree structure and adding method have an advantage of permitting more input terminals of adders to contain information about the input values to the adder tree structure. Therefore, the adders are used more efficiently and less adders are required to perform a specific function.

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San Jose, CA, United States of America

Steve C Hale