Fixed-Point Toolbox

Fixed-Point Computation

Fixed-Point Toolbox uses MATLAB syntax to support fixed-point computation. The toolbox provides the following functions and operators:

• Basic arithmetic, relational, logical, and bitwise operations
• Square root and convolution functions
• Statistical functions, such as min and max
• User-selected overflow and rounding modes to govern all arithmetic

The toolbox lets you use global or local settings for performing fixed-point arithmetic. When using global settings, fixed-point variables in the MATLAB session share a single set of arithmetic attributes. Global settings facilitate the process of converting a design from floating-point to fixed-point. When using local settings, fixed-point variables have their own attached arithmetic attributes. Local settings provide the user with better control over the details of each arithmetic operation.

There are four modes for performing fixed-point computations:

• Fully automatic mode, enabling you to use up to 65,535 bits for the sum or product
• Fully specified mode, letting you indicate the word length and binary point location for the sum or product
• Two partially automatic modes, in which the binary point location is set automatically but you can specify the word length of the sum or product

Using the plotting and visualization functions in MATLAB, you can visualize fixed-point data objects created in Fixed-Point Toolbox and analyze the results of your fixed-point design.