The fractional field in fixed-point representation determines where the decimal point is placed within the number, dividing the integer and fractional parts.
In fixed-point representation, numbers are stored in binary form with a fixed number of bits dedicated to the integer part and a fixed number of bits devoted to the fractional part. The fractional field, also known as the fractional part or fraction bits, determines the position of the decimal point within the number.
For example, let’s consider a fixed-point representation with 8 bits total, where 4 bits are assigned to the integer part and 4 bits are assigned to the fractional part:
0000 . 0000
In this representation, the first 4 bits are dedicated to the integer part (in this case, all zeros), and the next 4 bits represent the fractional part (again, all zeros). The position of the decimal point is determined by these 4 fractional bits. For example, if the fractional bits were set to 0101, the number represented would be 0.01012, which is 0.312510 in decimal.