Data Type Conversion and Casting

Conversion from one data type to another

Data type conversion and casting refers to changing from one data type to another. Fixed-Point Designer™ lets you create and optimize data types that meet numerical accuracy requirements and target hardware constraints.

Topics

Parameter and Signal Conversions

Conversions of data types of parameters and signals in Simulink® simulations.

Conversions and Arithmetic Operations

Example highlighting how the data types are converted and arithmetic operations are performed on inputs and parameters in the Simulink software.

Fixed-Point Arithmetic

Addition, subtraction, multiplication, casts, modulo, and two’s complement arithmetic.

Cast from Doubles to Fixed Point

Example based on the fxpdemo_dbl2fix model, which highlights many of the key features of the Fixed-Point Designer software.

Display Port Data Types

Three parts of the port display for fixed-point signals: the data type, the number of bits, and the scaling.

fi Objects and C Integer Data Types

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

Cast fi Objects

Information on casting fi objects.

Featured Examples

Double to Fixed-Point Conversion

Double to Fixed-Point Conversion

How to convert signals between built-in and fixed-point data types and illustrates how fixed-point data types affect the representable precision and range. The fixed-point data type used in this model is fixdt(1,5,2), which is a signed 5-bit number with 2 bits to the right of the binary point:

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Fixed-Point to Fixed-Point Conversion

Fixed-Point to Fixed-Point Conversion

Convert from one fixed-point data type to another fixed-point data type. In this case the conversion is between sfix32_En2 and ufix8_En1, meaning:

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Fixed-Point to Fixed-Point Inherited Conversion

Fixed-Point to Fixed-Point Inherited Conversion

Use the FixPt To FixPt Inherited block. Because Simulink® propagates data types throughout a block diagram, fixed-point utility modeling can be templatized for multiple use scenarios. The data type inheritance capability can be given additional information through the use of various relative-type specifications. The FixPt To FixPt Inherited block provides a way to specify that "this signal should have the same fixed-point data type as that signal" by wiring it up to the signals of interest.

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Fixed-Point Designer Documentation

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