This design is a ISDB-S3-LDPC-BCH Decoder IP, ready to license, verified and packaged, and supplied as a portable and synthesizable Verilog IP. The system was designed to be used in conjunction ...

So the code instructs the FPGA (or, more accurately, the Verilog compiler) to examine the number and set dispoutput based on the input. The <= character, by the way, are a non-blocking assignment.