关于verilog的各个基本模块的源代码，如加法器，寄存器，选择器及各个测试文件

fp add is floating point addition file

The Nexys4 DDR board is a complete, ready-to-use digital circuit development platform based on the latest Artix-7™ Field Programmable Gate Array (FPGA) Xilinx® . With its large, high-capacity FPGA (Xilinx part number XC7A100T-1CSG324C)