Range Over Channels in Verilog

In a previous example, we saw how for loops provide iteration over basic data structures. In Verilog, we can use similar constructs to iterate over values in an array or to simulate channel-like behavior.

module range_over_channels;
  
  reg [7:0] queue [1:0];
  integer i;

  initial begin
    // We'll iterate over 2 values in the `queue` array.
    queue[0] = "one";
    queue[1] = "two";

    // This `for` loop iterates over each element in `queue`.
    // Since Verilog doesn't have built-in channels, we use an array to simulate it.
    for (i = 0; i < 2; i = i + 1) begin
      $display(queue[i]);
    end
  end

endmodule

To run this Verilog code, you would typically use a Verilog simulator. The output would be:

one
two

This example demonstrates how to iterate over elements in an array, which is the closest equivalent to ranging over a channel in Verilog. Since Verilog is a hardware description language, it doesn’t have direct equivalents for channels or dynamic data structures. Instead, we use fixed-size arrays and for loops to achieve similar functionality.

Note that in Verilog, we don’t need to explicitly close the array as we would with channels in some other languages. The iteration naturally terminates when we reach the end of the array.

This example also shows that it’s possible to iterate over all elements in a fixed-size array, which is conceptually similar to receiving all values from a channel before it’s closed in other languages.