Qr Code Tool

[Alysha]

Noand low code users will still need developers and engineers to help build their dreams. That brings me to the second big concern from developers: do low and no code tools lower overall dependency on developers? What does that mean for their jobs?

In comparison to using the S-Function Builder or writing an S-function, Legacy Code Tool is easier to use and generates optimized code (does not generate wrapper code) often required by embedded systems. However, consider alternative approaches for a hybrid system, such as a system that includes a plant and controller, or a system component written in a language other than C or C++. Alternative approaches are more flexible in that they support more features and programming languages.

The following diagram illustrates a general procedure for using the Legacy Code Tool. Integrate C Functions into Simulink Models with Legacy Code Tool provides an example that uses the Legacy Code Tool to transform an existing C function into a C MEX S-function.

If you have a Simulink Coder product license, see Import Calls to External Code into Generated Code with Legacy Code Tool (Simulink Coder) for information on using the Legacy Code Tool for code generation.

Suppose that you have a C function that outputs the value of its floating-point input multiplied by two. The function is defined in a source file named doubleIt.c, and its declaration exists in a header file named doubleIt.h.

Specify appropriate values for fields in the Legacy Code Tool data structure to identify properties of the existing C function. For example, specify the C function source and header filenames by entering the following commands at the MATLAB command prompt:

You must also specify information about the S-function that the Legacy Code Tool produces from the C code. For example, specify a name for the S-function and its output function declaration by entering:

The Legacy Code Tool configures the block to use the C MEX S-function created in the previous step. Also, the tool masks the block such that it displays the value of its OutputFcnSpec property (see the description of the legacy_code function).

In Simulink, create a Simulink.Bus object to represent a structure type. Use bus signals in a model to represent structured signals and states. Create MATLAB structures in a workspace or in a block parameter dialog box to represent parameter structures.

For information about buses, see Composite Interface Guidelines. For information about parameter structures, see Organize Related Block Parameter Definitions in Structures. To create bus objects, see Create Simulink Bus Objects.

Specify the prototype of the output function, which the model calls every simulation step, by copying the prototype of the external function myFcn. Set the names of the arguments to u1, p1, and y1 to represent the input argument, the parameter argument, and the output argument. Use the syntax [1] to specify that each argument is a pointer.

Use the function legacy_code to create the S-function and the corresponding C MEX executable from the specification, def. Specify the option 'generate_for_sim' to prepare the S-function for normal and accelerated simulations.

To use the S-Function block in your model, create a bus signal of type sigStructType to use as the block input. The block output is also a bus signal. The block mask accepts a parameter, P1. To set the value of the parameter, use a MATLAB structure whose fields match those of the structure type paramStructType.

In the Constant block dialog box, the Constant value parameter is set to a structure whose fields match those of the structure type sigStructType. On the Signal Attributes tab, Output data type is set to the bus object sigStructType.

The first step to using the Legacy Code Tool is to register one or more MATLAB structures with fields that represent properties of the existing C code and the S-function being generated. The registration process is flexible. You can choose to set up resources and initiate registration in a variety of ways, including

The InitializeConditionsFcnSpec, OutputFcnSpec, StartFcnSpec, and TerminateFcnSpec fields defined in the Legacy Code Tool data structure (see the description of the legacy_code function) require character vector values that adhere to a specific syntax format. The required syntax format enables the Legacy Code Tool to map the return value and arguments of an existing C function to the return value, inputs, outputs, parameters, and work vectors of the S-function that the tool generates.

The argument specification defines one or more data type and token pairs that represent the input, output, parameter, and work vector arguments of the existing C function. The function input and output arguments map to block input and output ports and parameters map to workspace parameters.

If your function requires a Simulink S-function block with multiple input and output ports, map function arguments to input ports using a uniquely numbered u token. For output ports, use a uniquely numbered y token. These tokens are described in the preceding argument specification table. For example, consider the following C function prototype:

The resulting S-function block includes three input ports and two output ports. The first input maps to function argument u1, the second input to u2, and the third input to u3. For the output ports, the function argument y1[1] maps to the first output, and argument y2[1] maps to the second output. For another example of mapping a function prototype to multiple input and output ports, see Using Buses with Legacy Functions Having Structure Arguments.

You must supply the header file that defines the structure of the bus, defines the enum type, or defines the data type with the same name as an alias. The structure of the bus declared in the header file must match the structure of the bus object (for example, the number and order of elements, data types and widths of elements, and so on). For an example, see Using Buses with Legacy Functions Having Structure Arguments.

You must declare the data as a Simulink.NumericType object (unspecified scaling is not supported). For examples, see Fixed Point Signals in Legacy Functions and Fixed Point Parameters in Legacy Functions.

Limited to use with Simulink built-in data types. To specify a complex data type, enclose the built-in data type within angle brackets () and prepend the word complex (for example, complex). For an example, see Complex Signals in Legacy Function.

The MATLAB, Simulink, and Simulink Coder products store multidimensional array data in column-major format as a vector. If your external function code is written for row-major data, use convertNDArrayToRowMajor S-function option in legacy_code.

For a multidimensional signal, you can use the size function to determine the number of elements in the signal. For examples, see Lookup Tables Implemented in Legacy Functions and Multi-Dimensional Signals in Legacy Functions.

For a given Legacy Code Tool data structure, the data type and size of input, output, parameter, and work vector arguments must be the same across function specifications for StartFcnSpec, InitializeConditionsFcnSpec, OutputFcnSpec, and TerminateFcnSpec.

Function specifications you define for the StartFcnSpec, InitializeConditionsFcnSpec, or TerminateFcnSpec cannot access input or output arguments. For StartFcnSpec and InitializeConditionsFcnSpec, you can access output ports if the S-Function option outputsConditionallyWritten is set to true. With this option setting, the generated S-Function specifies that the memory associated with each output port cannot be overwritten and is global (SS_NOT_REUSABLE_AND_GLOBAL).

Generate a C MEX S-function based on the information defined in the structure. Call legacy_code with 'sfcn_cmex_generate' as the first argument and the name of the data structure as the second argument.

Compile and link the S-function. This step assumes that a C compiler is set up for your MATLAB installation. Call legacy_code with 'compile' as the first argument and the name of the data structure as the second argument.

Informational messages similar to the following appear in the MATLAB command window and a dynamically loadable executable results. On a 32-bit Windows system, the Simulink software names the file ex_sfun_doubleit.mexw32.

As a convenience, you can generate, compile, and link the S-function in a single step by calling legacy_code with the character vector 'generate_for_sim'. The function also generates a TLC file for accelerated simulations, if the Options.useTlcWithAccel field of the Legacy Code Tool data structure is set to 1.

You have the option of using the Legacy Code Tool to generate a masked S-function block (graphical representation) that is configured to call a generated C MEX S-function. To generate such a block, call legacy_code with 'slblock_generate' as the first argument and the name of the Legacy Code Tool data structure as the second argument.

If the specified model (for example, myModel) exists, legacy_code opens the model and adds the masked S-function block described by the Legacy Code Tool data structure. If the model does not exist, the function creates a new model with the specified name and adds the masked S-function block.

Generate a TLC block file for the S-function by calling the legacy_code function with 'sfcn_tlc_generate' as the first argument and the name of the Legacy Code Tool data structure as the second argument.

You can have multiple registration files in the same folder and generate an S-function for each file with a single call to legacy_code. Likewise, you can use a single call to legacy_code in order to compile and link the S-functions and another to generate corresponding TLC block files, if appropriate.

You can deploy the S-functions that you generate with the Legacy Code Tool for use by others. To deploy an S-function for simulation use only, you need to share only the compiled dynamically loadable executable.

3a8082e126