Fixed-Point Basics in MATLAB

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

To assign a fixed-point data type to a number or variable in MATLAB®, use the fi object. In the fi constructor, you can specify other numeric type properties, such as word length and fraction length, and properties that control the arithmetic of fixed-point data.


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fiConstruct fixed-point numeric object
ufiConstruct unsigned fixed-point numeric object
sfiConstruct signed fixed-point numeric object
fimathSet fixed-point math settings
fiprefSet fixed-point preferences
numerictypeConstruct numerictype object
accumposAdd two fi objects or values
accumnegSubtract two fi objects or values
quantizeQuantize fixed-point numbers
binBinary representation of stored integer of fi object
decUnsigned decimal representation of stored integer of fi object
doubleDouble-precision floating-point real-world value of fi object
hexHexadecimal representation of stored integer of fi object
removefimathRemove fimath object from fi object
setfimathAttach fimath object to fi object
globalfimathConfigure global fimath and return handle object
removeglobalfimathprefRemove global fimath preference
resetglobalfimathSet global fimath to MATLAB factory default
storedIntegerStored integer value of fi object
storedIntegerToDoubleConvert stored integer value of fi object to built-in double value
halfConstruct half-precision numeric object
pow10Base 10 power and scale half-precision numbers
rsqrtReciprocal square root
fmaMultiply and add using fused multiply add approach


embedded.fiFixed-point numeric object
embedded.fimathfimath object
embedded.numerictypenumerictype object


Ways to Construct fi Objects

Teaches you how to create fi objects

Set Up Fixed-Point Objects

Basic information on using fi objects

Cast fi Objects

Shows you how to cast fi objects

Compute Slope and Bias

Describes slope-bias scaling and how to compute it

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?

Explains the difference between fixed-point data types and built-in integer data 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.

Featured Examples