Computing method and computing device for floating-point mathematic operation using lookup table

A computing device for floating-point mathematic operation using look-up table, comprising:

• a first look-up table unit group used for receiving a plurality of index blocks and performing look-up operation using the index blocks as index to generate a plurality of look-up table results, wherein a bit arrangement or a format conversion is performed on a floating-point input data to generate the plurality of index blocks, a second index block of the index blocks including a plurality of first dummy bits and a combination of a sign and an exponent of the floating-point input data, and a third index block of the index blocks including a plurality of second dummy bits and a mantissa of the floating-point input data;
• and
• an operation unit used for performing operation on the look-up table results of the first look-up table unit group to generate an operation output.