Verilog function

Verilog functions are reusable blocks of code that perform specific operations and return a value. They are typically used to simplify the design and improve readability by encapsulating common functionalities.

In Verilog, functions can be declared within modules or at the module level. They are defined using the `function` keyword and should include a return type, a function name, and input/output declarations. Here's an example of a simple Verilog function:

function automatic int add_numbers(int a, int b);
  input int a;
  input int b;
  int sum;

  sum = a + b;
  return sum;
endfunction

In this example, the function named `add_numbers` takes two integer inputs `a` and `b`, and returns an integer value (`int`). It calculates the sum of `a` and `b` and assigns it to the variable `sum`, which is then returned by the function.

Functions in Verilog can only contain sequential statements and cannot include any continuous assignments or delays. They can be called from within other modules or functions using the function name and passing appropriate arguments.

It's important to note that Verilog functions are not synthesizable and are only used for simulation purposes. If you need to design hardware using Verilog, you should use modules and instantiate them instead.