Sharing requirements for generating reusable code from atomic and virtual subsystems in Simulink models from R2021a documentation.
Generate Reusable Code for Subsystems
HDL Coder™ can detect atomic subsystems that are identical, or identical except for their mask parameter values, at any level of the model hierarchy, and generate a single reusable HDL module or entity. The reusable HDL code is generated as a single file and instantiated multiple times.
Requirements for Generating Reusable Code for Atomic Subsystems
To generate reusable HDL code for atomic subsystems:
- The DefaultParameterBehavior Simulink® Configuration Parameter must be Inlined. You can set this parameter at the command line by using the set_param or hdlsetup function. To specify this setting in the Configuration Parameters dialog box, you must have Simulink Coder™.
- Logging functionality must not be used, such as signal logging or using blocks such as To Workspace or To File.
- The atomic subsystems must be identical, or identical except for their mask parameter values.
- MaskParameterAsGeneric must be on. For more information, see Generate parameterized HDL code from masked subsystem.
- Mask parameters must be nontunable. The code generator does not share atomic subsystems with mask parameters that are tunable.
- Mask parameter data types cannot be double or single.
- The tunable parameter must be used in only Constant or Gain blocks.
- Port data types must match.If you change the value of the tunable mask parameter, the output port data type can change. If one of the atomic subsystems has a different port data type, the code generated for that subsystem also differs.
Requirements for Generating Reusable Code for Virtual Subsystems
Set SubsystemReuse option to 'Atomic and Virtual' (new in 21a)
To generate reusable HDL code for virtual subsystems:
- The DefaultParameterBehavior Simulink Configuration Parameter must be Inlined. You can set this parameter at the command line by using the set_param or hdlsetup function. To specify this setting in the Configuration Parameters dialog box, you must have Simulink Coder.
- Logging functionality must not be used, such as signal logging or using blocks such as To Workspace or To File.
- The virtual subsystems must be identical, or identical except for their mask parameter values.
- SubsystemReuse must be set to 'Atomic and Virtual'.
- Setting SubsystemReuse to 'Atomic and Virtual' reduces artificial algebraic errors and improves the recognition of identical subsystems, irrespective of their topology within the rest of the design. Identification of similar subsystems can help resource sharing.
- To set these values to your required setting, in the MATLAB Command Window, enter:hdlset_param('myHDLModel', 'SubsystemReuse', 'Atomic and Virtual')
- Alternatively, you can set this option from the top-level HDL Code Generation pane in the Configuration Parameters dialog box. Under Global Settings > Coding style, you can change the Code reuse setting to the required option.
- The previous commands set the SubsystemReuse option for your project. To set this option for only the current code generation session, enter:makehdl(<DUT system>, 'SubsystemReuse', 'Atomic and Virtual')
- MaskParameterAsGeneric must be on. For more information, see Generate parameterized HDL code from masked subsystem.
- Mask parameters must be nontunable. The code generator does not share atomic subsystems with mask parameters that are tunable.
- Mask parameter data types cannot be double or single.
- The tunable parameter must be used in only Constant or Gain blocks.
- Port data types must match.If you change the value of the tunable mask parameter, the output port data type can change. If one of the atomic subsystems has a different port data type, the code generated for that subsystem also differs.
