Code You Can Replace From Simulink Models

Code that the code generator replaces depends on the code replacement library (CRL) that you use. By default, the code generator does not apply a code replacement library. Your choice of libraries is dependent on product licensing and whether you have access to custom libraries.

For information on how to explore functions and operators that a code replacement library supports, see Choose a Code Replacement Library.

Math Functions – Simulink Support

When generating C/C++ code from a Simulink^® model, depending on code replacement libraries available in your development environment, you can configure the code generator to replace instances of the following math functions with application-specific implementations. To replace math functions that you use inside MATLAB function blocks, the functions must also meet the requirements in Code You Can Replace from MATLAB Code.

Function	Data Type Support	Scalar, Vector, Matrix Support	Real, Complex Support
`abs`¹	Integer Floating point Fixed point	Scalar Vector Matrix	Real
`acos`	Floating point	Scalar	Real Complex input/complex output Real input/complex output
`acosd`²	Floating point	Scalar Vector Matrix	Real Complex
`acosh`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`acot`²	Floating point	Scalar Vector Matrix	Real Complex
`acotd`²	Floating point	Scalar Vector Matrix	Real Complex
`acoth`²	Floating point	Scalar Vector Matrix	Real Complex
`acsc`²	Floating point	Scalar Vector Matrix	Real Complex
`acscd`²	Floating point	Scalar Vector Matrix	Real Complex
`acsch`²	Floating point	Scalar Vector Matrix	Real Complex
`asec`²	Floating point	Scalar Vector Matrix	Real Complex
`asecd`²	Floating point	Scalar Vector Matrix	Real Complex
`asech`²	Floating point	Scalar Vector Matrix	Real Complex
`asin`	Floating point	Scalar	Real Complex input/complex output Real input/complex output
`asind`²	Floating point	Scalar Vector Matrix	Real Complex
`asinh`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`atan`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`atan2`³	Floating point	Scalar Vector Matrix	Real
`atan2d`²	Floating point	Scalar Vector Matrix	Real
`atand`²	Floating point	Scalar Vector Matrix	Real Complex
`atanh`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`ceil`	Floating-point Scalar	Floating-point Scalar	Floating-point Scalar
`circularIndex` — Delay block with Use circular buffer for state selected.	Integer	Scalar	Real
`cos`³	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`cosd`²	Floating point	Scalar Vector Matrix	Real Complex
`cosh`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`cot`²	Floating point	Scalar Vector Matrix	Real Complex
`cotd`²	Floating point	Scalar Vector Matrix	Real Complex
`coth`²	Floating point	Scalar Vector Matrix	Real Complex
`csc`²	Floating point	Scalar Vector Matrix	Real Complex
`cscd`²	Floating point	Scalar Vector Matrix	Real Complex
`csch`²	Floating point	Scalar Vector Matrix	Real Complex
`exactrSqrt` — Sqrt block with: Function set to `rSqrt` Method set to `Exact`	Integer Floating point	Scalar	Real
`exp`	Floating point	Scalar Vector Matrix	Real
`fix`	Floating point	Scalar	Real
`floor`	Floating-point Scalar	Floating-point Scalar	Floating-point Scalar
`fmod`⁴	Floating point	Scalar	Real
`frexp`	Floating point	Scalar	Real
`hypot`	Floating point	Scalar Vector Matrix	Real
`ldexp`	Floating point	Scalar	Real
`ln`	Floating point	Scalar	Real
`log`	Floating point	Scalar Vector Matrix	Real
`log10`	Floating point	Scalar Vector Matrix	Real
`log2`²	Floating point	Scalar Vector Matrix	Real Complex
`max`	Integer Floating point Fixed point	Scalar	Real
`min`	Integer Floating point Fixed point	Scalar	Real
`mod`	Integer Floating point	Scalar Vector Matrix	Real
`pow`	Floating point	Scalar Vector Matrix	Real
`rem`	Floating point	Scalar Vector Matrix	Real
`round`	Floating point	Scalar	Real
`rSqrt`	Integer Floating point	Scalar Vector Matrix	Real
`saturate`	Integer Floating point Fixed point	Scalar Vector Matrix	Real
`sec`²	Floating point	Scalar Vector Matrix	Real Complex
`secd`²	Floating point	Scalar Vector Matrix	Real Complex
`sech`²	Floating point	Scalar Vector Matrix	Real Complex
`sign`	Integer Floating point Fixed point	Scalar Vector Matrix	Real
`signPow` — Math Function block with: Function set to `pow` Signed power enabled	Floating point	Scalar Vector Matrix	Real
`sin`³	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`sincos`³	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`sind`²	Floating point	Scalar Vector Matrix	Real Complex
`sinh`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`sqrt`	Integer Floating point Fixed point	Scalar Vector Matrix	Real
`tan`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
`tand`²	Floating point	Scalar Vector Matrix	Real Complex
`tanh`	Floating point	Scalar Vector Matrix	Real Complex input/complex output Real input/complex output
¹ Wrap on integer overflow only. Clear block parameter Saturate on integer overflow. ² Only when used with the MATLAB Function block. ³ Supports the CORDIC approximation method and the Lookup approximation method. ⁴ Stateflow^® support only.

Math Functions – Stateflow Support

When generating C/C++ code from Stateflow charts, depending on code replacement libraries available in your development environment, you can configure the code generator to replace instances of the following math functions with application-specific implementations.

Function	Data Type Support	Scalar, Vector, Matrix Support	Real, Complex Support
`abs`¹	Integer Floating point	Scalar	Real
`acos`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`acosd`³	Floating point	Scalar Vector Matrix	Real Complex
`acot`³	Floating point	Scalar Vector Matrix	Real Complex
`acotd`³	Floating point	Scalar Vector Matrix	Real Complex
`acoth`^3,5	Floating point	Scalar Vector Matrix	Real Complex
`acsc`³	Floating point	Scalar Vector Matrix	Real Complex
`acscd`³	Floating point	Scalar Vector Matrix	Real Complex
`acsch`³	Floating point	Scalar Vector Matrix	Real Complex
`asec`³	Floating point	Scalar Vector Matrix	Real Complex
`asecd`³	Floating point	Scalar Vector Matrix	Real Complex
`asech`³	Floating point	Scalar Vector Matrix	Real Complex
`asin`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`asind`³	Floating point	Scalar Vector Matrix	Real Complex
`atan`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`atan2`²	Floating point	Scalar Vector Matrix	Real
`atan2d`³	Floating point	Scalar Vector Matrix	Real
`atand`³	Floating point	Scalar Vector Matrix	Real Complex
`ceil`	Floating-point Scalar	Floating-point Scalar	Floating-point Scalar
`cos`³	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`cosd`³	Floating point	Scalar Vector Matrix	Real Complex
`cosh`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`cot`³	Floating point	Scalar Vector Matrix	Real Complex
`cotd`³	Floating point	Scalar Vector Matrix	Real Complex
`coth`³	Floating point	Scalar Vector Matrix	Real Complex
`csc`³	Floating point	Scalar Vector Matrix	Real Complex
`cscd`³	Floating point	Scalar Vector Matrix	Real Complex
`csch`³	Floating point	Scalar Vector Matrix	Real Complex
`exp`	Floating point	Scalar	Real
`floor`	Floating-point Scalar	Floating-point Scalar	Floating-point Scalar
`fmod`	Floating point	Scalar	Real
`hypot`³	Floating point	Scalar Vector Matrix	Real
`ldexp`	Floating point	Scalar	Real
`log`²	Floating point	Scalar Vector Matrix	Real Complex
`log10`²	Floating point	Scalar Vector Matrix	Real Complex
`log2`³	Floating point	Scalar Vector Matrix	Real Complex
`max`	Integer Floating point	Scalar	Real
`min`	Integer Floating point	Scalar	Real
`pow`	Floating point	Scalar	Real
`sec`³	Floating point	Scalar Vector Matrix	Real Complex
`secd`³	Floating point	Scalar Vector Matrix	Real Complex
`sech`³	Floating point	Scalar Vector Matrix	Real Complex
`sin`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`sind`³	Floating point	Scalar Vector Matrix	Real Complex
`sinh`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`sqrt`	Floating point	Scalar	Real
`tan`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
`tand`³	Floating point	Scalar Vector Matrix	Real Complex
`tanh`²	Floating point	Scalar Vector Matrix	Real Complex Complex input/complex output Real input/complex output
¹ Wrap on integer overflow only. ² For models involving vectors or matrices, the code generator replaces only functions coded in the MATLAB^® action language. ³ The code generator replaces only functions coded in the MATLAB action language.

Memory Functions

Depending on code replacement libraries available in your development environment, you can configure the code generator to replace instances of the following memory functions with application-specific implementations.

Function	Data Type Support	Scalar, Vector, Matrix Support	Real, Complex Support
`memcmp`	Void pointer (`void*`)	Scalar Vector Matrix	Real Complex
`memcpy`	Void pointer (`void*`)	Scalar Vector Matrix	Real Complex
`memset`	Void pointer (`void*`)	Scalar Vector Matrix	Real Complex
`memset2zero`	Void pointer (`void*`)	Scalar Vector Matrix	Real Complex

Some target processors provide optimized functions to set memory to zero. Use the code replacement library programming interface to replace the memset2zero function with more efficient target-specific functions.

Nonfinite Functions

Depending on code replacement libraries available in your development environment, you can configure the code generator to replace instances of the following nonfinite functions with application-specific implementations.

Function	Data Type Support	Scalar, Vector, Matrix Support	Real, Complex Support
`getInf`	Floating point	Scalar	Real
`getMinusInf`	Floating point	Scalar	Real
`getNaN`	Floating point	Scalar	Real
`rtIsInf`	Floating point	Scalar	Real Complex
`rtIsNaN`	Floating point	Scalar	Real Complex

Mutex and Semaphore Functions

Mutex and semaphore functions control access to resources shared by multiple processes in multicore target environments. MathWorks^® provides code replacement libraries that support mutex and semaphore replacement for Rate Transition and Task Transition blocks on Windows^®, Linux^®, Mac, and VxWorks^® platforms.

Generated mutex and semaphore code typically consists of:

In model initialization code, an initialization function call to create a mutex or semaphore to control entry to a critical section of code.
In model step code:
- Before code for a data transfer between tasks enters the critical section, mutex lock or semaphore wait function calls to reserve a critical section of code.
- After code for a data transfer between tasks finishes executing the critical section, mutex unlock or semaphore post function calls to release the critical section of code.
In model termination code, an optional destroy function call to explicitly delete the mutex or semaphore.

Depending on code replacement libraries available in your development environment, you can configure the code generator to replace instances of the following mutex and semaphore functions with application-specific implementations.

Function	Key
Mutex Destroy	`RTW_MUTEX_DESTROY`
Mutex Init	`RTW_MUTEX_INIT`
Mutex Lock	`RTW_MUTEX_LOCK`
Mutex Unlock	`RTW_MUTEX_UNLOCK`
Semaphore Destroy	`RTW_SEM_DESTROY`
Semaphore Init	`RTW_SEM_INIT`
Semaphore Post	`RTW_SEM_POST`
Semaphore Wait	`RTW_SEM_WAIT`

Operators

When generating C/C++ code from a Simulink model, depending on code replacement libraries available in your development environment, you can configure the code generator to replace instances of the following operators with application-specific implementations.

Mixed data type support indicates that you can specify different data types for different inputs.

Operator	Key	Data Type Support	Scalar, Vector, Matrix Support	Real, Complex Support
Addition (`+`)¹	`RTW_OP_ADD`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Subtraction (`-`)¹	`RTW_OP_MINUS`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Multiplication (`*`)²	`RTW_OP_MUL`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Division (`/`)	`RTW_OP_DIV`	Integer Floating point Fixed-point Mixed	Scalar	Real Complex
Data type conversion (cast)	`RTW_OP_CAST`	Integer Floating point³ Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Shift left (`<<`)	`RTW_OP_SL`	Integer Fixed-point Mixed	Scalar Vector Matrix⁴	Real
Shift right arithmetic (`>>`)⁵	`RTW_OP_SRA`	Integer Fixed-point Mixed	Scalar Vector Matrix⁴	Real
Shift right logical (`>>`)	`RTW_OP_SRL`	Integer Fixed-point Mixed	Scalar Vector Matrix⁴	Real
Element-wise matrix multiplication (`.*`)⁶	`RTW_OP_ELEM_MUL`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Matrix right division (`/`)	`RTW_OP_RDIV`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Matrix left division (`\`)	`RTW_OP_LDIV`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Matrix inversion (`inv`)	`RTW_OP_INV`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Complex conjugation	`RTW_OP_CONJUGATE`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Transposition (`.'`)	`RTW_OP_TRANS`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Hermitian (complex conjugate) transposition (`'`)	`RTW_OP_HERMITIAN`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Multiplication with transposition²	`RTW_OP_TRMUL`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Multiplication with Hermitian transposition²	`RTW_OP_HMMUL`	Integer Floating point Fixed-point Mixed	Vector Matrix	Real Complex
Multiplication followed by shift right arithmetic (`u1*u2>>u3`)⁷	`RTW_OP_MUL_SRA`	Integer Fixed-point	Scalar	Real
Multiplication followed by division (`u1*u2/u3`)⁸	`RTW_OP_MULDIV`	Integer Fixed-point	Scalar	Real
Greater than (`>`)	`RTW_OP_GREATER_ THAN`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Greater than or equal (`>=`)	`RTW_OP_GREATER_ THAN_OR_EQUAL`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Less than (`<`)	`RTW_OP_LESS_THAN`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Less than or equal (`<=`)	`RTW_OP_LESS_THAN_ OR_EQUAL`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Equal (`==`)	`RTW_OP_EQUAL`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
Not equal (`!=`)	`RTW_OP_NOT_EQUAL`	Integer Floating point Fixed-point Mixed	Scalar Vector Matrix	Real Complex
¹ See Replace Addition and Subtraction Operator Code for details to consider when defining mappings for addition and subtraction code replacements. ² Can map to Basic Linear Algebra Subroutine (BLAS) multiplication functions. ³ Scaled floating point is not supported. ⁴ Shift operator replacement with matrix data is supported for shift values that you specify with an input port. Replacement is not supported for shift values that you specify in a block parameter dialog. ⁵ The code generator converts some arithmetic shift rights to logical shift rights. To avoid unexpected results, when creating a code replacement library that includes a table entry for an arithmetic shift right implementation, also include an entry for a logical shift right implementation. ⁶ Use the multiplication (``) operator (`RTW_OP_MUL`) for scalar multiplication. ⁷ Requires scalar, real, or fixed-point data types with zero bias; output type of the multiplication operation to accommodate all possible output values; shift operand is an unsigned integer; and net slope is equal to 1 (`U1_slope U2_slope == Mul_output_slope` and `Mul_output_slope == output_slope_of_shift_operation`). ⁸ Requires scalar, real, or fixed-point data types with zero bias; output type of the multiplication operation to accommodate all possible output values; and net slope is equal to 1 (`U1_slope * U2_slope == Mul_output_slope == U3_slope * Div_output_slope`).

Blocks You Can Replace

This table indicates the blocks you can replace, the key for each block, block parameter settings that you can specify, and valid block parameter arguments for each block. The table also indicates which block parameter settings and block parameter arguments you are required to set in a block replacement entry for each block. For fixed-point implementations for supported blocks, you must also specify the required data type parameters.

Block	Key	Block Parameters	Block Parameter Arguments	Data Type Block Parameters for Fixed-Point Implementations
Discrete FIR Filter	`DiscreteFir`	Coefficient source (`CoefSource`) － Required Filter structure (`FilterStructure`) － Required Coefficients (`Coefficients`) Input processing (`InputProcessing`) － Required Initial states (`InitialStates`) Show enable port (`ShowEnablePort`) External reset (`ExternalReset`) Sample time (`SampleTime`)	Coefficients (`Coefficients`) Initial states (`InitialStates`)	Tap sum (`TapSumDataTypeStr`) － Required Coefficients (`CoefDataTypeStr`) － Required Coefficients minimum (`CoeffMin`) － Not supported. Do not specify this parameter. Coefficients maximum (`CoeffMax`) － Not supported. Do not specify this parameter. Product output (`ProductDataTypeStr`)－ Required Accumulator (`AccumDataTypeStr`)－ Required State (`StateDataTypeStr`) － Required Output (`OutDataTypeStr`) － Required Output minimum (`OutMin`) － Not supported. Do not specify this parameter. Output maximum (`OutMax`) － Not supported. Do not specify this parameter. Lock data type settings against changes by the fixed-point tools (`LockScale`) － Required Integer rounding mode (`RndMeth`) － Required Saturate on integer overflow (`SaturateOnIntegerOverflow`) － Required
Biquad Filter (DSP System Toolbox)	`Biquad Filter`	Coefficient source (`FilterSource`) － Required Filter structure (`IIRFiltStruct`) － Required SOS Matrix (Mx6) (`BiQuadCoeffs`) Scale values (`ScaleValues`) Input processing (`InputProcessing`) － Required Initial conditions (`IC`) Initial conditions on zeros side (`ICnum`) Initial conditions on poles side (`ICden`) Scale values mode (`ScaleValueMode`) Action when the a0 values of the SOS matrix are not one (`a0Flag`) Optimize unity scale values (`OptimizeUnityScaleValues`)	SOS Matrix (Mx6) (`BiQuadCoeffs`) Initial conditions (`IC`) Initial conditions on zeros side (`ICnum`) Initial conditions on poles side (`ICden`) Scale values (`ScaleValue`)	Rounding mode (`RoundingMode`) － Required Saturate on integer overflow (`OverflowMode`) － Required Coefficients (`firstCoeffMode`) － Required Product output (`prodOutputMode`) － Required Accumulator (`accumMode`) － Required States (`memoryMode`) － Required Output (`outputMode`) － Required Section input (`stageInputMode`) － Required Section output (`stageOutputMode`) － Required Multiplicand (`multiplicandMode`) － Required Lock data type settings against changes by the fixed-point tools (`LockScale`) － Required
FFT (DSP System Toolbox)	`FFT`	FFT implementation (`FFTImplementation`) － Required Output in bit-reversed order (`BitRevOrder`) － Required Divide output by FFT length (`Normalize`) － Required Inherit FFT length from input dimensions (`InheritFFTLength`) － Required FFT length (`FFTLength`) － Required if `InheritFFTLength` is off Wrap input data when FFT length is shorter than input length (`WrapInput`) － Required if `InheritFFTLength` is off	None	Fixed-point implementations are not supported.
IFFT (DSP System Toolbox)	`IFFT`	FFT implementation (`FFTImplementation`) － Required Input is in bit-reversed order (`BitRevOrder`) － Required Input is conjugate symmetric (`cs_in`) － Required Divide output by FFT length (`Normalize`) － Required Inherit FFT length from input dimensions (`InheritFFTLength`) － Required FFT length (`FFTLength`) － Required if `InheritFFTLength` is off Wrap input data when FFT length is shorter than input length (`WrapInput`) － Required if `InheritFFTLength` is off	None	Fixed-point implementations are not supported.
FIR Decimation (DSP System Toolbox)	`FIR Decimation`	Coefficient source (`FilterSource`) － Required Decimation factor (`D`) － Required FIR filter coefficients (`h`) － Required if `FilterSource` is dialog parameters Filter structure (`FiltStruct`) － Required Input processing (`InputProcessing`) － Required Rate options (`framing`) － Required Filter object (`FilterObject`) － Required if `FilterSource` is filter object Output buffer initial conditions (`OutputBufInitCond`) － Required if `framing` is allow multirate processing Allow arbitrary frame length for fixed-size input signals (`AllowArbitraryInputLength`) － Required if `framing` is enforce single-rate processing	Decimation factor (`D`) Filter object (`FilterObject`)	Fixed-point implementations are not supported.
FIR Interpolation (DSP System Toolbox)	`FIR Interpolation`	Coefficient source (`FilterSource`) － Required Interpolation factor (`L`) － Required FIR filter coefficients (`h`) － Required if `FilterSource` is dialog parameters Input processing (`InputProcessing`) － Required Rate options (`framing`) － Required Filter object (`FilterObject`) － Required if `FilterSource` is filter object Output buffer initial conditions (`OutputBufInitCond`) － Required if `framing` is allow multirate processing	Interpolation factor (`L`) Filter object (`FilterObject`)	Fixed-point implementations are not supported.