Decoding method, memory storage device and memory control circuit unit

A memory storage device, comprising:

• a connection interface unit, used for coupling to a host system a rewritable non-volatile memory module, and
• a memory control circuit unit, coupled to the connection interface unit and the rewritable non-volatile memory module,
• wherein the memory control circuit unit supports a plurality of decoding modes, the decoding modes respectively correspond to a threshold value, and a distribution of the threshold value corresponds to error correction abilities of the decoding modes,
• the memory control circuit unit is used for:
• sending a read command sequence, which instructs to read first data from the rewritable non-volatile memory module;
• performing a first decoding operation on the first data;
• obtaining a decoding parameter according to an execution result of the first decoding operation;
• and
• performing a second decoding operation on the first data based on a first decoding mode among the decoding modes according to a relative numerical relationship between the decoding parameter and the threshold value.

A memory control circuit unit, used for controlling a rewritable non-volatile memory module, the memory control circuit unit comprising:

• a host interface, used for coupling to the host system;
• a memory interface, used for coupling to the rewritable non-volatile memory module a decoding circuit;
• and
• a memory management circuit, coupled to the host interface, the memory interface, and the decoding circuit,
• wherein the decoding circuit supports a plurality of decoding modes, the decoding modes respectively correspond to a threshold value, and a distribution of the threshold value corresponds to error correction abilities of the decoding modes,
• the memory management circuit unit is used for:
• sending a read command sequence, which instructs to read first data from the rewritable non-volatile memory module;
• performing a first decoding operation on the first data by the decoding circuit;
• obtaining a decoding parameter according to an execution result of the first decoding operation;
• and
• instructing the decoding circuit to perform a second decoding operation on the first data based on a first decoding mode among the decoding modes according to a relative numerical relationship between the decoding parameter and the threshold value.