最长的那个句子，求sum的赋值语句就是FIR滤波器的计算过程，将二进制乘法转化为移位运算。对于小数点后的乘数是向左移，小数点前的乘数是往右移位。 -The longest sentence, find the sum of the assignment statement is the calculation of the FIR filter, the binary multiplication into shift operation. Multiplier after the deci