这段程序主要是实现了两个16进制的数据相加减，主要思想是由32位的进位加法器的来。目标板是spartan 3的实验板。-This program is to achieve a two-phase addition and subtraction of data 16 hex, the main idea is to carry the 32-bit adder to. Target board is spartan 3 development board.