Embedded Target for Texas Instruments C6000 DSPs

Fixed-Point Numbers

In digital hardware, numbers are stored in binary words. A binary word is a fixed-length sequence of binary digits (1s and 0s). How hardware components or software functions interpret this sequence of 1s and 0s is defined by the data type.

Binary numbers are represented as either fixed-point or floating-point data types. A fixed-point data type is characterized by the word size in bits, the binary point, and whether it is signed or unsigned. The position of the binary point is the means by which fixed-point values are scaled and interpreted.

For example, a binary representation of a fractional fixed-point number (either signed or unsigned) is shown below.

where

• is the ith binary digit.
• is the word size in bits.
• is the location of the most significant (highest) bit (MSB).
• is the location of the least significant (lowest) bit (LSB).
• The binary point is shown four places to the left of the LSB. In this example, therefore, the number is said to have four fractional bits, or a fraction length of four.

About the C62x DSP Library

Signed Fixed-Point Numbers