16位有符号整数除法，将商并入移位后的被除数，节省资源。-16-bit signed integer division, will shift into business after the dividend, saving resources.

lattice isplever7竟然没有除法库,只好在网上找了老外写的vhdl除法器-lattice isplever7 Treasury did not divide, so the Internet to find a foreigner to write the VHDL divider