coder.dataAlignment - Specify data alignment for global or entry-point/exported

function input and output arguments - MATLAB (original) (raw)

Main Content

Specify data alignment for global or entry-point/exported function input and output arguments

Syntax

Description

coder.dataAlignment(['varName'](#bvn0llo-1-varName),[align_value](#bvn0llo-1-align%5Fvalue)) specifies data alignment in MATLAB® code for the variable (varName), which is imported data or global (exported) data. The code generator aligns the imported or exported data to the alignment boundary (align_value).

example

Examples

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An example function that specifies data alignment for imported data.

function y = importedDataExampleFun(x1,x2)

coder.dataAlignment('x1',16); % Specifies information coder.dataAlignment('x2',16); % Specifies information coder.dataAlignment('y',16); % Specifies information

y = x1 + x2;

end

An example function that specifies data alignment for exported data.

function a = exportedDataExampleFun(b)

global z; coder.dataAlignment('z',8);

a = b + z;

end

Input Arguments

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The varName is a character array of the variable name that requires alignment information specification.

The alignvalue is an integer number which should be a power of 2. This number specifies the power-of-2 byte alignment boundary.

Limitations

Limitations on variables supported by coder.dataAlignment directive:

• Only use coder.dataAlignment to specify alignment information for function inputs, outputs, and global variables.
• coder.dataAlignment supports only matrix types, including matrix of complex types.
• For exported custom storage classes (CSCs), coder.dataAlignment supports only ExportedGlobal. You can specify alignment information for any imported CSCs.
• The code generator ignores coder.dataAlignment for non-ERT or non-ERT derived system target files.
• Global variables tagged using the coder.dataAlignment directive from within a MATLAB function block are ignored. Set the alignment value on the corresponding Data Store Memory.
• The coder.dataAlignment function generates an error if a code replacement library is not specified. For more information, see Provide Data Alignment Specifications for Compilers.

Tips

• To prevent inlining a function containing an aligned variable in the generated code, a best practice is to call coder.inline('never') in your code.

Extended Capabilities

Version History

Introduced in R2017a