Decompression engine supporting large match offsets using external memory

A decompression apparatus, comprising:

• a cache memory;
• and
• a decoder, to:
• receive a compressed input data stream comprising literals and matches, wherein (i) each literal represents a data value, and (ii) each match represents a respective sequence of literals by a respective offset pointing to a respective past occurrence of the sequence of literals;
• decompress the input data stream by replacing each match with the corresponding past occurrence, so as to produce an output data stream;
• and
• output the output data stream to an external memory and to the cache memory,
• wherein, in replacing a given match with the corresponding past occurrence, the decoder is to:
• when the offset indicates that the past occurrence is cached in the cache memory, retrieve the past occurrence from the cache memory;
• and
• when the offset indicates that the past occurrence is not contained in the cache memory, fetch the past occurrence from the external memory.

A decompression apparatus, comprising:

• a cache memory;
• and
• a decoder, to:
• receive a compressed input data stream comprising literals and matches, wherein (i) each literal represents a data value, and (ii) each match comprises an offset value pointing to a corresponding past occurrence of a respective sequence of literals;
• decompress the input data stream by replacing each match with the corresponding past occurrence, so as to produce an output data stream;
• and
• output the output data stream to an external memory and to the cache memory,
• wherein, in replacing a given match with the corresponding past occurrence, the decoder is to:
• when the offset indicates that the past occurrence is cached in the cache memory, retrieve the past occurrence from the cache memory;
• and
• when the offset indicates that the past occurrence is not contained in the cache memory, fetch the past occurrence from the external memory.

A peripheral device, comprising:

• a host interface, to communicate with a host;
• and
• a decompression engine comprising a cache memory, the decompression engine to:
• receive a compressed input data stream comprising literals and matches, wherein (i) each literal represents a data value, and (ii) each match represents a respective sequence of literals by a respective offset pointing to a respective past occurrence of the sequence of literals;
• decompress the input data stream by replacing each match with the corresponding past occurrence, so as to produce an output data stream;
• and
• output the output data stream to an external memory of the host and to the cache memory,
• wherein, in replacing a given match with the corresponding past occurrence, the decompression engine is to:
• when the offset indicates that the past occurrence is cached in the cache memory, retrieve the past occurrence from the cache memory;
• and
• when the offset indicates that the past occurrence is not contained in the cache memory, fetch the past occurrence over the host interface from the external memory.