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Specify alignment boundary of a complex type



addComplexTypeAlignment(hDataAlign,baseType,alignment) specifies the alignment boundary of real and complex data members of a complex type.

The starting memory address of the real and imaginary part of complex variables produced by the code generator with the specified type are a multiple of the specified alignment boundary. The code generator replaces operations in generated code when both of these conditions are true:

  • A code replacement table entry has a complex argument with a data alignment requirement that is less than or equal to the alignment boundary value

  • The entry satisfies all other code replacement match criteria.

To use this function, your code replacement library registration file must include additional compiler data alignment information, such as alignment syntax.


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This example shows how to specify a 16-byte alignment boundary for complex int8 types by adding the addComplexTypeAlignment line to your code replacement library registration file.

function rtwTargetInfo(cm)
% rtwTargetInfo function to register a code replacement library (CRL)
% for use with  code generation

  % Register the CRL defined in local function locCrlRegFcn


% Local function to define a CRL containing crl_table_mmul_4x4_single_align
function thisCrl = locCrlRegFcn

  % create an alignment specification object, assume gcc
  as = RTW.AlignmentSpecification;
  as.AlignmentType = {'DATA_ALIGNMENT_LOCAL_VAR', ...
                      'DATA_ALIGNMENT_GLOBAL_VAR', ...
  as.AlignmentSyntaxTemplate = '__attribute__((aligned(%n)))';
  as.SupportedLanguages={'c', 'c++'};

  % add the alignment specification object
  da = RTW.DataAlignment;
  da.addComplexTypeAlignment('int8', 16);

  % add the data alignment object to target characteristics
  tc = RTW.TargetCharacteristics;
  tc.DataAlignment = da;

  % Instantiate a CRL registry entry
  thisCrl = RTW.TflRegistry;

  % Define the CRL properties
  thisCrl.Name = 'Data Alignment Example';
  thisCrl.Description = 'Example of replacement with data alignment';
  thisCrl.TableList = {'crl_table_mmul_4x4_single_align'};
    thisCrl.TargetCharacteristics = tc;


Input Arguments

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The hDataAlign is a handle to a data alignment object, previously returned by hDataAlign = RTW.DataAlignment.

Example: da

The baseType is a character vector or string scalar that specifies a built-in data type such as int8 or long.

Example: 'int8'

The alignment is a positive integer that is a power of 2. This value specifies the alignment boundary.

Example: 16

Version History

Introduced in R2014a