说明：  笔者长期从事移动通信系统的无线链路调制与解调、物理层实现方面的工作。在移动通信GSM系统中，我们进行语音或者业务信道解调时，都会遇到CRC的求解。通常在硬件DSP实现时，特别是40位CRC求解时候，由于生成多项式有41项，DSP最大一次能处理40位，所以使用单个寄存器会遇到一些困难，那么以下这个程序将会解决这一困难（这是针对定点DSP、C55xx的编程实现方法）。
(The author has long been engaged in mobile communication system modulation and demodulation of wireless links, the physical layer to achieve work. GSM in the mobile communications system, we have a voice or channel demodulation operations, it will encounter the solution of CRC. DSP hardware usually realize, especially when solving the 40 CRC, as the generation polynomial has 41, DSP can handle the largest 40, so using a single register may encounter some difficulties, then following this process will solve this One difficulty (which is for fixed-point DSP, C55xx realize programming methods).)