Data storage device and control method for non-volatile memory

A data storage device, comprising:

• a non-volatile memory;
• and
• a memory controller and a temporary storage,
• wherein:
• the memory controller accesses the non-volatile memory as requested by a host;
• the memory controller plans a data cache space in the temporary storage;
• the memory controller dynamically updates mapping information on the temporary storage to manage physical space information mapped to a logical address recognized by the host;
• the memory controller uses a first bit to an Nth bit of the physical space information to represent dummy information, or to indicate a physical space of the non-volatile memory or a cache address of the data cache space, without using additional bits to map the physical space information to the non-volatile memory or the data cache space, where N is a number greater than one;
• among numbers formed by the first to the Nth bit, the memory controller uses numbers corresponding to non-existent physical space of the non-volatile memory to represent the dummy information, or to map the physical space information to the non-volatile memory or the data cache space;
• the memory controller uses a mask to mask the physical space information and thereby generates a judgment value;
• when the judgment value is a first value, the memory controller determines that the physical space information is the dummy information;
• when the judgment value is a second value, the memory controller maps the physical space information to the data cache space;
• and
• when the judgment value is neither the first value nor the second value, the memory controller maps the physical space information to the non-volatile memory.