Programmable variable length decoder circuit and method

Abstract

Apparatuses and methods for decoding a bit stream of variable-length and fixed-length codewords representing encoded digital content. A decoder includes a memory for storing microinstructions that control the decoder. The decoder further includes a first barrel shifter for extracting a first bit field from the bit stream, a position of the first bit field being specified by the microinstruction, and a second barrel shifter for extracting a second bit field from the bit stream, a position of the second bit field being specified by the microinstructions. A microprogram counter keeps an address of a currently-executing microinstruction of the microinstructions, where a next state of the microprogram counter is determined by the microinstructions and the first bit field. A data converter modifies a value of the second bit field according to the microinstructions. A data storage stores either data in the microinstructions or an output of the data converter as decoded data values.

Dependencies are inferred from the claim text.