Range Over Iterators in VHDL

-- In VHDL, we define a library and use clause instead of importing packages
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;

-- Entity declaration (similar to a package in other languages)
entity List is
    generic (
        TYPE_WIDTH : integer := 32  -- Assuming 32-bit integers
    );
    port (
        -- We'll define ports if needed for external communication
    );
end entity List;

-- Architecture (implementation) of the List entity
architecture Behavioral of List is
    -- Type definitions
    type element;
    type element_ptr is access element;
    type element is record
        next : element_ptr;
        val  : integer;
    end record;

    type list_type is record
        head : element_ptr;
        tail : element_ptr;
    end record;

    -- Function to push an element to the list
    procedure Push(lst : inout list_type; v : in integer) is
        variable new_element : element_ptr;
    begin
        new_element := new element'(next => null, val => v);
        if lst.tail = null then
            lst.head := new_element;
            lst.tail := new_element;
        else
            lst.tail.next := new_element;
            lst.tail := new_element;
        end if;
    end procedure;

    -- Function to generate Fibonacci numbers
    -- Note: VHDL doesn't have built-in iterators, so we'll use a different approach
    function genFib(n : integer) return integer is
        variable a, b, temp : integer := 1;
    begin
        for i in 3 to n loop
            temp := b;
            b := a + b;
            a := temp;
        end loop;
        return a;
    end function;

begin
    -- Main process (similar to the main function)
    process
        variable lst : list_type := (head => null, tail => null);
        variable current : element_ptr;
    begin
        -- Push elements to the list
        Push(lst, 10);
        Push(lst, 13);
        Push(lst, 23);

        -- Print elements of the list
        current := lst.head;
        while current /= null loop
            report "Element: " & integer'image(current.val);
            current := current.next;
        end loop;

        -- Generate and print Fibonacci numbers
        for i in 1 to 6 loop
            report "Fibonacci(" & integer'image(i) & "): " & integer'image(genFib(i));
        end loop;

        wait;
    end process;
end architecture Behavioral;

In this VHDL translation:

We define a List entity with a generic parameter for the data width.
The element and list_type are defined as records, similar to structs in other languages.
The Push procedure is implemented to add elements to the list.
Instead of using iterators, which are not native to VHDL, we implement a genFib function that generates the nth Fibonacci number.
The main functionality is implemented in a process, which is VHDL’s equivalent of a main function.
We use VHDL’s report statement to print values, as VHDL is primarily used for hardware description and simulation.
The infinite Fibonacci sequence is replaced with a finite loop generating the first 6 Fibonacci numbers.

Note that VHDL is a hardware description language, so concepts like dynamic memory allocation and iterators don’t directly translate. This example demonstrates how to implement similar functionality in a hardware-oriented context.

Generics in VHDL

Errors in VHDL

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Range Over Iterators in VHDL