Fixed-Point Basics in MATLAB

Fixed-point numbers, scale, cast, precision, arithmetic operations


fi Construct fixed-point numeric object
ufi Construct unsigned fixed-point numeric object
sfi Construct signed fixed-point numeric object
fimath Set fixed-point math settings
fipref Set fixed-point preferences
numerictype Construct numerictype object
accumpos Add two fi objects or values
accumneg Subtract two fi objects or values
quantize Quantize fixed-point numbers
bin Binary representation of stored integer of fi object
dec Unsigned decimal representation of stored integer of fi object
double Double-precision floating-point real-world value of fi object
hex Hexadecimal representation of stored integer of fi object
removefimath Remove fimath object from fi object
setfimath Attach fimath object to fi object
globalfimath Configure global fimath and return handle object
removeglobalfimathpref Remove global fimath preference
resetglobalfimath Set global fimath to MATLAB factory default
storedInteger Stored integer value of fi object
storedIntegerToDouble Convert stored integer value of fi object to built-in double value

Classes Fixed-point numeric object
embedded.fimath fimath object
embedded.numerictype numerictype object

Examples and How To

Ways to Construct fi Objects

Teaches you how to create fi objects

Set Up Fixed-Point Objects

Basic information on using fi objects

Perform Fixed-Point Arithmetic

"Perform Fixed-Point arithmetic"

Cast fi Objects

Shows you how to cast fi objects

Perform Binary-Point Scaling

Perform binary-point scaling in fixed point.

Compute Slope and Bias

Describes slope-bias scaling and how to compute it

Set Fixed-Point Math Attributes

This example shows how to set fixed point math attributes in MATLAB code.

View Fixed-Point Number Circles

Define unsigned and signed two's complement integer and fixed-point numbers.


fi Object Properties

Tells you how to find more information about the properties associated with fi objects, and shows you how to set these properties

fi Objects and C Integer Data Types

Compares ANSI C integer data type ranges, conversions, and exception handling with those of fi objects

fi Object Display Preferences Using fipref

Gives examples of using fipref objects to set display preferences for fi objects

Underflow and Overflow Logging Using fipref

Gives examples of using fipref objects to set logging preferences for fi objects

Data Type Override Preferences Using fipref

Describes how to use the fipref object to perform data type override

fi Objects with Simulink

Describes the ways you can use Fixed-Point Designer™ fi objects with Simulink® models

fi Objects with DSP System Toolbox

Describes how to pass fixed-point data back and forth between the MATLAB® workspace and Simulink models using DSP System Toolbox™ blocks


What Is the Difference Between Fixed-Point and Built-In Integer Types?

There are several distinct differences between fixed-point data types and the built-in integer types in MATLAB.

Negative Fraction Length

A negative fraction length occurs when the input value of a fi object contains trailing zeros.

Fraction Length Greater Than Word Length

A fraction length greater than the word length of a fixed-point number occurs when the number has an absolute value less than one and contains leading zeros.

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