High-speed lossless data compression system based on content addressable memory

A lossless data compression and addressing memory technology, applied in memory systems, electrical digital data processing, memory address/allocation/relocation, etc., can solve the problems of limited RAM resources of hardware chips, indeterminate search cycles, and low compression rates. , to reduce the search delay, solve the speed problem, and improve the compression rate

Inactive Publication Date: 2012-07-18
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problems of low compression rate, consumption of limited RAM resources in the hardware chip, and uncertain search cycle in the prior art, as well as the problem of address conflicts in dictionary search using the hash table address module, the present invention proposes a content-based High Speed ​​Lossless Data Compression System with Addressable Memory

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  • High-speed lossless data compression system based on content addressable memory
  • High-speed lossless data compression system based on content addressable memory
  • High-speed lossless data compression system based on content addressable memory

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specific Embodiment approach 1

[0019] Embodiment one: a high-speed lossless data compression system based on content addressable memory, which includes a clock module 4, an input data cache module 1, a dictionary module 5, an LZW algorithm core module 2 and an output encoding module 3, wherein:

[0020] The clock module 4 is used to provide all clock signals required by the system;

[0021] The input data cache module 1 is composed of the first-in-first-out memory FIFO inside the FPGA, which is used to cache the input data, and provides the input data to the LZW algorithm core module in the form of data stream for compression;

[0022] The LZW algorithm core module 2 is used to receive the data stream output by the input data cache module 1; it is also used to compress the input data stream through the initialization, search, update and application of the LZW algorithm to the dictionary module 5, and compress the compressed The generated code stream is input to the output encoding module 3;

[0023] The ou...

specific Embodiment approach 2

[0031] Embodiment 2: This embodiment further describes the structure of the dictionary module 5 in the content-addressable memory-based high-speed lossless data compression system described in Embodiment 1.

[0032] The CAM that constitutes dictionary module 5 described in the present embodiment is made up of 32 memory pages and an input address decoding module, an output address decoding module and a control module, and each memory page is made up of 16 memory banks; The address of the memory bank is 9 bits, and each bit width is 17 bits. The first 9 bits are used to store the prefix Prefix of the entity Entry, and the last 8 bits are used to store the suffix Suffix of the entity Entry. The structure of each memory bank is the same. The memory bank is composed of a comparator and a flip-flop, and the flip-flop is used to store data. When the write enable signal is valid, when a certain memory bank is selected, new data is written into the flip-flop in the memory bank to perfor...

specific Embodiment approach 3

[0053] Embodiment 3: This embodiment further defines the structure of the LZW algorithm core module 2 in the content-addressable memory-based high-speed lossless data compression system described in Embodiment 1 or 2. The LZW algorithm core module 2 in this embodiment is composed of two nested state machines.

[0054] The two state machines described in this embodiment can be used to implement the system main program and the data compression program respectively. Wherein, the state machine for realizing data compression is nested in the state machine for realizing the main program of the system.

[0055] In this embodiment, the state machine used to implement the main program of the system has four working states, the work done by each working state and the mutual conversion process between the states can be found in Figure 6 Shown:

[0056] The idle state is used to judge the state of the reset signal Reset, and when the reset signal is valid Reset=1, it enters the initial...

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Abstract

The invention provides a high-speed lossless data compression system based on a content addressable memory, which relates to the technical field of the data compression of a hardware system. The invention solves the problems of low compression rate, heavy consumption of limited RAM resources in a hardware chip, indefinite search cycle, and the like, and solves the problem that address conflict exists in the dictionary searching which is realized by adopting a hash table address module. The invention comprises a clock module, an input data buffer module, a dictionary module, an LZW algorithm kernel module and an output encoding module, wherein, the dictionary module is constructed by the CAM inside an FPGA, the bit width of the CAM is 17, and the depth of the CAM is 512; the address of thememory in the CAM corresponds to the code of the LZW algorithm in the LZW algorithm kernel module, and the memory comprises a comparator and a trigger; the trigger is used for storing data, and the comparator is used for comparing input data with the data in the trigger and outputting a matching signal. The data compression system realizes the high-speed lossless data compression based on the FPGAand enlarges the range of application.

Description

technical field [0001] The invention relates to the technical field of data compression of hardware systems. Background technique [0002] In the lossless data compression hardware implementation based on the LZW (Lempel-Ziv-Welch) algorithm, compression rate and compression speed are two important indicators for measuring compression performance. Usually, after the compression algorithm is implemented correctly, the compression rate only depends on the characteristics of the data source to be compressed, such as its redundancy and local correlation, while the compression speed has a large room for variation. The current general data processing capacity All can reach about 20KB / s. In some low-speed occasions, this rate can fully meet the requirements, but once the system requires an increase in real-time capability, it cannot be applied. To this end, we need to increase the data compression speed as much as possible, so we first need to analyze the compression algorithm pr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03M7/30G06F12/08G06F12/10G06F12/0811
Inventor 王立欣吕超宋巍罗伟林张玉霞
Owner HARBIN INST OF TECH
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