Data decompression device, memory system, and method

A data decompression device configured to decompress a compressed data string obtained by dictionary-based compression, the compressed data string including first compressed data having a first offset, the data decompression device comprising:

• a dictionary circuit including at least one first dictionary configured to store first decompressed data corresponding to the first compressed data, and at least one second dictionary configured to store the first decompressed data;
• an assignment circuit configured to assign the first compressed data to at least one dictionary of the at least one first dictionary or the at least one second dictionary;
• a reference circuit configured to read, using the first offset, the first decompressed data from the at least one dictionary to which the first compressed data is assigned;
• and
• a generation circuit configured to generate a decompressed data string including the first decompressed data read by the reference circuit, wherein:
• a storage size of each of the at least one first dictionary is larger than a storage size of each of the at least one second dictionary;
• the first offset is configured to indicate a storage location of at least one dictionary of the at least one first dictionary or the at least one second dictionary;
• and
• in a case where the compressed data string includes second compressed data having a second offset indicating a storage location of at least one dictionary of the at least one first dictionary or the at least one second dictionary;
• the assignment circuit is configured to:
• assign, based on the first offset, the first compressed data to at least one dictionary of the at least one first dictionary or the at least one second dictionary;
• and
• assign, based on the second offset, the second compressed data to at least one dictionary of the at least one first dictionary or the at least one second dictionary, wherein the at least one dictionary to which the second compressed data is assigned is different from the at least one dictionary to which the first compressed data is assigned;
• the reference circuit is configured to perform a first read and a second read in parallel, wherein
• during the first read, the reference circuit is configured to read the first decompressed data using the first offset from the at least one dictionary to which the first compressed data is assigned, and
• during the second read, the reference circuit is configured to read the second decompressed data corresponding to the second compressed data using the second offset from the at least one dictionary to which the second compressed data is assigned;
• and
• the generation circuit is configured to generate the decompressed data string including the first decompressed data and the second decompressed data.