C++ Prerequisites for SystemC

Before diving into SystemC, it is crucial to understand that SystemC is not a new language. It is entirely built as a C++ class library. If you are coming from Verilog or VHDL, you might be tempted to treat SystemC like a hardware description language. However, if you do not understand the underlying C++, you will quickly become frustrated when the compiler throws massive template errors.

Just like learncpp.com teaches C++ from the ground up, this page outlines exactly what C++ concepts you must master before proceeding.

1. Object-Oriented Programming (OOP)

SystemC modules (sc_module) are just C++ classes. You need to be deeply comfortable with:

• Classes and Structs: Creating them, member variables, and member functions.
• Constructors: SystemC relies heavily on constructors (SC_CTOR) to register processes and bind ports.
• Inheritance: sc_module inherits from sc_object. You will frequently use public inheritance when defining custom interfaces.
• Polymorphism and Virtual Functions: In TLM (Transaction Level Modeling), you will define purely virtual interfaces and implement them in your target modules.

2. Pointers and References

Hardware ports are essentially safe pointers to signals.

• Pass-by-Reference (&): Passing large transaction payloads efficiently.
• Pointers (*): Dynamically allocating modules, or passing pointers to arrays.
• Smart Pointers: In advanced TLM and SCV (SystemC Verification Library), you will use scv_smart_ptr to handle memory automatically and avoid segmentation faults.

3. C++ Templates

SystemC ports, signals, and FIFOs are templated classes. When you write sc_in<bool>, you are instantiating an sc_in template for the boolean type.

You must understand:

• How to pass basic types to templates (sc_signal<int>).
• How to pass user-defined structs to templates (sc_signal<MyStruct>).
• Operator Overloading: SystemC overloads the << operator for sensitivity lists and port binding, and the = operator for reading/writing signals. It is not bit-shifting; it is C++ operator overloading.

4. The Standard Template Library (STL)

You will not write your own linked lists. You will use the STL.

• std::vector for dynamic arrays of ports or modules.
• std::string for dynamic module naming.
• std::cout and std::endl for simulation logging.

Summary

If any of these concepts are entirely foreign to you, please pause and read through the corresponding chapters on LearnCpp.com. SystemC is incredibly powerful, but its power comes from leveraging advanced C++ paradigms to mimic hardware concurrency.

Once you are comfortable with C++, proceed to the next tutorial to install the Accellera SystemC library.