## Considerations for DPI Component Generation with MATLAB

You can export a MATLAB^{®} function as a component with a direct programming interface (DPI) for use
in a SystemVerilog simulation. HDL Verifier™ wraps generated C code with a DPI wrapper that communicates with a
SystemVerilog thin interface function in a SystemVerilog simulation.

For MATLAB, you generate the component using the `dpigen`

function.

**Note**

You must have a MATLAB Coder™ license to use this feature.

### Supported MATLAB Data Types

Supported MATLAB data types are converted to SystemVerilog data types, as shown in this
table. When using the `dpigen`

function, use the
`PortsDataType`

property to select ```
Compatible C
type
```

, `Logic vector`

, or ```
Bit
vector
```

data types.

**Generated SystemVerilog Types**

MATLAB | SystemVerilog | ||
---|---|---|---|

Compatible C Type | Logic Vector | Bit Vector | |

`uint8` | `byte unsigned` | `logic [7:0] ` | `bit [7:0] ` |

`uint16` | `shortint unsigned` | `logic [15:0] ` | `bit [15:0] ` |

`uint32` | `int unsigned` | `logic [31:0]` | `bit [31:0]` |

`uint64` | `longint unsigned` | `logic [63:0]` | `bit [63:0]` |

`int8` | `byte` | `logic signed [7:0]` | `bit signed [7:0]` |

`int16` | `shortint` | `logic signed [15:0]` | `bit signed [15:0]` |

`int32` | `int` | `logic signed [31:0]` | `bit signed [31:0]` |

`int64` | `longint` | `logic signed [63:0]` | `bit signed [63:0]` |

`logical` | `byte unsigned` | `logic [0:0]` | `bit [0:0]` |

`fi` (fixed-point data type) | Depends on the fixed-point word length. If the fixed-point word length is greater than the host word size (for example, 64-bit vs. 32-bit), then this data type cannot be converted to a SystemVerilog data type by MATLAB Coder and you will get an error. If the fixed-point word length is less than or equal to the host word size, MATLAB Coder converts the fixed-point data type to a built-in C type. |
The logic vector length ( |
The bit vector length ( |

`single` | `shortreal` | ||

`double` | `real` | ||

`complex` | The coder flattens complex signals into real and imaginary parts in the SystemVerilog component. | ||

vectors, matrices | arrays For example, a 4-by-2 matrix in MATLAB is converted into a one-dimensional array of eight elements in SystemVerilog. By default, the coder flattens matrices in column-major order. To change to row-major order, use the | ||

`structure` | The coder flattens structure elements into separate ports in the SystemVerilog component. | ||

enumerated data types | `enum` |

### Generated Shared Library

Function `dpigen`

automatically compiles the shared library
needed to run the exported DPI component in the SystemVerilog environment. The
makefile that builds the shared library has the extension
`_rtw.mk`

. For example, for `fun.m`

, the make file
name is `fun_rtw.mk`

.

During compilation, the function `dpigen`

generates a library
file.

Windows

^{®}64:_win64.dll`function`

Linux

^{®}:.so`function`

* function* is the name of the MATLAB function you generated the DPI component from.

**Note**

If you use 64-bit MATLAB on Windows, you get a 64-bit DLL, which can be used only with a 64-bit HDL simulator.

Make sure that your MATLAB version matches your HDL simulator version.

### Generated Test Bench

Function `dpigen`

also creates a test bench. You can use this
test bench to verify that the generated SystemVerilog component is functionally
equivalent to the original MATLAB function. The generator runs your MATLAB code to save input and output data vectors for use in the test bench.
This test bench is not intended as a replacement for a system test bench for your
own application. However, you can use the generated test bench as a starting example
when creating your own system test bench.

### Generated Outputs

C and header files from your algorithm, generated by MATLAB Coder

C and header files for the DPI wrapper, generated by HDL Verifier

SystemVerilog file that exposes the component and adds control signals

SystemVerilog package file that contains all the function declarations of the DPI component

SystemVerilog test bench (with the

`-testbench`

option)Data files used with the HDL simulator (with the

`-testbench`

option)HDL simulator scripts, such as

`*.do`

or`*.sh`

(with the`-testbench`

option)Makefile

`*.mk`

### Generated SystemVerilog Wrapper

#### Generated Control Signals

SystemVerilog code generated for a sequential function by function
`dpigen`

contains a set of control signals.

`clk`

: synchronization clock`clk_enable`

: clock enable`reset`

: asynchronous reset

When generating SystemVerilog for a combinational design, the generated code
does not have the above control signals. Specify sequential or combinational by
using the `ComponentTemplateType`

argument of the `dpigen`

function.

#### Generated Initialize Function

All SystemVerilog code generated by the `dpigen`

function
includes an `Initialize`

function. The
`Initialize`

function is called at the beginning of the
simulation.

For example:

import "DPI" function void DPI_Subsystem_initialize();

If the asynchronous reset signal is high (goes from 0 to 1),
`Initialize`

is called again.

### Simulation Considerations

When simulating the DPI component in your HDL environment,
`reset`

, `clock`

, and
`clk_enable`

behave as follows:

When

`clk_enable`

is`0`

, the DPI output function is not executed, and the output values are not updated.When

`clk_enable`

is`1`

and`reset`

is`0`

, the DPI output function is executed on the positive edge of the clock signal.When

`reset`

is`1`

, the internal state of the DPI component is set to its initial value. This action is equivalent to using the`clear`

function in MATLAB to update persistent variables. Then output values then reflect the DPI component initial state and current input values. For more details on persistent variables, see Persistent Variables.

### Limitations

Large fixed-point numbers that exceed the system word length are not supported.

Some optimizations, such as constant folding, are not supported because they change the interface of the generated C function. For more information, see MATLAB Coder Optimizations in Generated Code (MATLAB Coder).

HDL Verifier limits matrices and vectors to one-dimensional arrays in SystemVerilog. For example, a 4-by-2 matrix in MATLAB is converted to a one-dimensional array of eight elements in SystemVerilog.

The

`PostCodegen`

callback in configuration objects is not supported.