公开(公告)号：US20250077417A1

公开(公告)日：2025-03-06

申请号：US18801968

申请日：2024-08-13

Applicant: Kioxia Corporation

Inventor： Sho KODAMA ,  Masato SUMIYOSHI ,  Keiri NAKANISHI ,  Yosei TAKASAKI

IPC: G06F12/02 ,  G11C16/04 ,  G11C16/10 ,  H03M7/40

Abstract: According to one embodiment, a variable length coding device includes circuitry. The circuitry determines N code lengths corresponding to respective N symbols, based on a Huffman tree. In a case where the N code lengths include a first code length longer than a maximum code length, the circuitry selects a first symbol corresponding to the first code length from the N symbols, selects, from the N symbols, a second symbol corresponding to a second code length shorter than the maximum code length, changes the second code length corresponding to the second symbol to a code length obtained by adding one to the second code length, and changes the first code length corresponding to the first symbol to a code length equal to the changed second code length.

公开(公告)号：US20230283295A1

公开(公告)日：2023-09-07

申请号：US17941345

申请日：2022-09-09

Applicant: Kioxia Corporation

Inventor： Sho KODAMA ,  Masato SUMIYOSHI

IPC: H03M7/40 ,  H03M7/30

CPC classification number: H03M7/405 ,  H03M7/3077 ,  H03M7/4062

Abstract: According to one embodiment, a code table generation device includes a table generation unit, a merge unit and a tree generation unit. The table generation unit generates a frequency table including symbols and frequencies of occurrence respectively associated with the symbols, based on a frequency of occurrence for each symbol of input symbols. The merge unit acquires top K symbols in descending order of the frequencies of occurrence and remaining symbols from the symbols, divides the remaining symbols into one or more symbol sets, and determines a frequency of occurrence associated with a root node of each of subtrees correspond to the respective symbol sets. The tree generation unit generates a Huffman tree using the K symbols and the root node of each of the subtrees.

公开(公告)号：US20210288662A1

公开(公告)日：2021-09-16

申请号：US17010013

申请日：2020-09-02

Applicant: Kioxia Corporation

Inventor： Youhei FUKAZAWA ,  Keiri NAKANISHI ,  Sho KODAMA ,  Masato SUMIYOSHI ,  Kohei OIKAWA ,  Daisuke YASHIMA ,  Takashi MIURA ,  Zheye WANG

IPC: H03M7/40 ,  H03M7/30 ,  G06F40/126

Abstract: According to one embodiment, a compression device includes a dictionary based encoder, a second buffer, a comparator, and a compression data generator. The dictionary based encoder searches for second data at least partially matching first data from a first buffer, and acquires a first match position indicating a position of the second data in the first buffer and a match length indicating a matched length of the first and second data. The second buffer stores the previously acquired second match position with an index. The compression data generator generates first compressed data that includes the index assigned to the second match position in the second buffer and the match length when the first match position matches the second match position in the second buffer.

公开(公告)号：US20230070623A1

公开(公告)日：2023-03-09

申请号：US17653513

申请日：2022-03-04

Applicant: Kioxia Corporation

Inventor： Daisuke YASHIMA ,  Youhei FUKAZAWA ,  Sho KODAMA ,  Keiri NAKANISHI ,  Masato SUMIYOSHI ,  Kohei OIKAWA ,  Zheye WANG ,  Takashi MIURA

IPC: H03M7/30

Abstract: According to one embodiment, a data compression device includes a dictionary match determination unit, an extended matching generator, a match selector and a match connector. The dictionary match determination unit searches for first past input data matching first new input data. The extended matching generator compares second past input data subsequent to the first past input data with second new input data subsequent to the first new input data. The match selector generates compressed data by replacing a part of the input data with match information output from the dictionary match determination unit or the extended matching generator. The match connector replaces a plurality of match information in the compressed data with single match information.

公开(公告)号：US20220398019A1

公开(公告)日：2022-12-15

申请号：US17686246

申请日：2022-03-03

Applicant: KIOXIA CORPORATION

Inventor： Youhei FUKAZAWA ,  Sho KODAMA ,  Keiri NAKANISHI ,  Kohei OIKAWA ,  Takashi MIURA ,  Daisuke YASHIMA ,  Masato SUMIYOSHI ,  Zheye WANG

IPC: G06F3/06

Abstract: A compression device includes an analyzer circuit, a control circuit, a compressor circuit, and a selector circuit. The analyzer circuit is configured to analyze first data that is input thereto and generate one or more parameter values regarding data compression and/or decompression. The control circuit is configured to generate at least one compression mode information indicating whether or not compression is to be performed, based on the one or more parameter values. The compressor circuit is configured to compress the first data into second data according to the compression mode information. The selector circuit is configured to output the first data if not compressed or the second data if the first data is compressed, together with the compression mode information.

公开(公告)号：US20220353519A1

公开(公告)日：2022-11-03

申请号：US17868597

申请日：2022-07-19

Applicant: Kioxia Corporation

Inventor： Daisuke YASHIMA ,  Masato SUMIYOSHI ,  Keiri NAKANISHI ,  Takashi MIURA ,  Kohei OIKAWA ,  Sho KODAMA ,  Youhei FUKAZAWA ,  Zheye WANG

IPC: H04N19/423 ,  H04N19/146 ,  H04N19/13

Abstract: According to one embodiment, a memory system includes a frequency value update unit, a first intra-group rearranging unit, a second intra-group rearranging unit, and a routing unit. The frequency value update unit adds a first value to each of one or more first frequency values that are associated with one or more first symbols, respectively, in one or more entries in a table. The first intra-group rearranging unit rearranges first entries, which belong to a first group, using frequency values in the first entries. The second intra-group rearranging unit rearranges second entries, which belong to a second group lower than the first group, using frequency values. The routing unit rearranges at least one of the first entries and at least one of the second entries.

公开(公告)号：US20220294469A1

公开(公告)日：2022-09-15

申请号：US17304130

申请日：2021-06-15

Applicant: Kioxia Corporation

Inventor： Sho KODAMA ,  Masato SUMIYOSHI ,  Keiri NAKANISHI

IPC: H03M7/40 ,  G06F3/06

Abstract: According to one embodiment, a compression device includes a coding information generation unit. The unit determines code lengths that are respectively associated with a plurality of symbols, based on a frequency of occurrence of each of the plurality of symbols. When the plurality of symbols include one or more first symbols that are respectively associated with one or more first code lengths exceeding an upper limit, the unit changes the first code lengths to the upper limit, selects, from one or more second symbols of the plurality of symbols that are respectively associated with one or more second code lengths shorter than the upper limit, at least one symbol in descending associated code length order, changes at least one code length associated with the symbol to the upper limit.

公开(公告)号：US20220269416A1

公开(公告)日：2022-08-25

申请号：US17304025

申请日：2021-06-14

Applicant: Kioxia Corporation

Inventor： Sho KODAMA ,  Keiri NAKANISHI ,  Masato SUMIYOSHI ,  Zheye WANG ,  Kohei OIKAWA ,  Youhei FUKAZAWA ,  Daisuke YASHIMA ,  Takashi MIURA

IPC: G06F3/06 ,  H03M7/30

Abstract: According to one embodiment, a memory system includes a compressor configured to output second data obtained by compressing input first data and a non-volatile memory to which third data based on the second data output from the compressor is written. The compressor includes a dictionary coding unit configured to perform dictionary coding on the first data, an entropy coding unit configured to perform entropy coding on the result of the dictionary coding, a first calculation unit configured to calculate compression efficiencies of the dictionary coding and the entropy coding, and a first control unit configured to control an operation of at least one of the dictionary coding unit and the entropy coding unit based on the compression efficiencies and a power reduction level.

公开(公告)号：US20220187994A1

公开(公告)日：2022-06-16

申请号：US17471107

申请日：2021-09-09

Applicant: Kioxia Corporation

Inventor： Youhei FUKAZAWA ,  Kohei OIKAWA ,  Sho KODAMA ,  Keiri NAKANISHI ,  Takashi MIURA ,  Daisuke YASHIMA ,  Masato SUMIYOSHI ,  Zheye WANG

IPC: G06F3/06 ,  H03M7/30

Abstract: According to one embodiment, a compression device includes a first storage unit, a second storage unit, a calculation unit, and a comparison unit. The first storage unit stores addresses associated with hash values, respectively. The second storage unit includes storage areas specified by the addresses, respectively. The calculation unit determines a hash function to be used for first data in accordance with at least a part of the first data, and calculates a hash value using the hash function and at least a part of second data included in the first data. The comparison unit acquires third data from a storage area in the second storage unit specified by a first address, and compares the second data with the third data. The first address is stored in the first storage unit and is associated with the hash value.