如何管理联合和位域

Question

I have been trying to create a program that adds two positive fixed point numbers whose whole part is 5 bits and its decimal part is 3 bits but I have not succeeded, I know that it can be achieved with the handling of bit fields and unions but I have not found the goal. I would appreciate if someone could help me with this.

Answer 1

Let a be an integer object that represents a number a using a fixed-point representation with three fraction bits. Then a = 8• a , or, conversely, a = a /8.

Similarly, let b be an integer object that represents a number b with the same representation.

Then, since a = a /8 and b = b /8, we have a + b = a /8 + b /8 = a+b /8.

Therefore, the representation of the sum of the number represented by a and the number represented by b can be computed with a+b .

Answer 2

The bit fields in C programming can be defined using struct as shown below for task you want to perform.

struct decimalPoint
{
    unsigned int wholePart:5;
    unsigned int decimalPart:3;
};

Now since the way to definition of your data is ready you can perform addition of this data and store the result back to the same structure.