Struct Embedding in Verilog

Verilog supports module instantiation to express a more seamless composition of hardware designs. This is similar to the concept of embedding in other languages.

// Define a base module
module base(
    input wire [7:0] num,
    output reg [31:0] description
);
    always @(*) begin
        description = {"base with num=", num};
    end
endmodule

// A container module that instantiates a base module
module container(
    input wire [7:0] num,
    input wire [7:0] str,
    output wire [31:0] description
);
    // Instantiate the base module
    base base_inst (
        .num(num),
        .description(description)
    );

    // Additional logic for the container module
    wire [7:0] container_str;
    assign container_str = str;
endmodule

// Top-level module for testing
module testbench;
    reg [7:0] num;
    reg [7:0] str;
    wire [31:0] description;

    // Instantiate the container module
    container dut (
        .num(num),
        .str(str),
        .description(description)
    );

    initial begin
        // Initialize inputs
        num = 8'd1;
        str = "some name";

        // Display results
        #10;
        $display("co={num: %d, str: %s}", num, str);
        $display("describe: %s", description);
    end
endmodule

When creating modules in Verilog, we instantiate sub-modules explicitly. Here, the container module instantiates the base module.

We can access the base module’s outputs directly in the container module, e.g., description.

In Verilog, there’s no direct equivalent to method embedding. However, we can achieve similar functionality by instantiating modules and connecting their inputs and outputs.

The testbench module serves as the main entry point for simulation, similar to the main function in other languages.

To run this Verilog code, you would typically use a Verilog simulator like Icarus Verilog or ModelSim. The simulation might produce output similar to:

co={num: 1, str: some name}
describe: base with num=1

Note that Verilog, being a hardware description language, has significant differences from software programming languages. Concepts like interfaces and dynamic method calls don’t have direct equivalents. Instead, we focus on describing hardware structure and behavior.