Time Formatting Parsing in VHDL

Our first example demonstrates time formatting and parsing in VHDL. While VHDL doesn’t have built-in time manipulation libraries like other high-level languages, we can simulate some basic time operations using custom types and functions.

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;

entity TimeFormattingParsing is
end TimeFormattingParsing;

architecture Behavioral of TimeFormattingParsing is
    -- Custom time type
    type Time_Type is record
        year  : integer range 0 to 9999;
        month : integer range 1 to 12;
        day   : integer range 1 to 31;
        hour  : integer range 0 to 23;
        minute: integer range 0 to 59;
        second: integer range 0 to 59;
    end record;

    -- Function to format time as a string
    function format_time(t : Time_Type) return string is
    begin
        return integer'image(t.year) & "-" &
               integer'image(t.month) & "-" &
               integer'image(t.day) & " " &
               integer'image(t.hour) & ":" &
               integer'image(t.minute) & ":" &
               integer'image(t.second);
    end function;

    -- Procedure to simulate parsing time from a string
    procedure parse_time(s : in string; t : out Time_Type) is
    begin
        -- In a real implementation, this would parse the string
        -- For this example, we'll just set a fixed time
        t.year   := 2012;
        t.month  := 11;
        t.day    := 1;
        t.hour   := 22;
        t.minute := 8;
        t.second := 41;
    end procedure;

    signal current_time : Time_Type;
    signal parsed_time  : Time_Type;

begin
    process
    begin
        -- Set current time
        current_time <= (2023, 6, 15, 10, 30, 0);
        wait for 10 ns;

        -- Format and print current time
        report "Current time: " & format_time(current_time);

        -- Parse time from a string
        parse_time("2012-11-01T22:08:41", parsed_time);
        wait for 10 ns;

        -- Print parsed time
        report "Parsed time: " & format_time(parsed_time);

        wait;
    end process;

end Behavioral;

In this VHDL example, we’ve created a custom Time_Type to represent time, along with format_time function and parse_time procedure to simulate time formatting and parsing.

The format_time function converts a Time_Type record into a string representation.

The parse_time procedure simulates parsing a time string. In a real implementation, this would actually parse the input string, but for simplicity, we’re just setting a fixed time.

In the main process, we:

Set a current time
Format and print the current time
Simulate parsing a time string
Print the parsed time

This example demonstrates how you might approach time handling in VHDL, although it’s important to note that VHDL is primarily used for hardware description and simulation, so time handling is typically done differently compared to software programming languages.

To run this VHDL code, you would typically use a VHDL simulator such as ModelSim or GHDL. The exact commands would depend on your simulation environment.

$ ghdl -a timeformattingparsing.vhdl
$ ghdl -e timeformattingparsing
$ ghdl -r timeformattingparsing

This would compile and run the VHDL code, producing output similar to:

Current time: 2023-6-15 10:30:0
Parsed time: 2012-11-1 22:8:41

Remember, VHDL is used for hardware description, so this example is more of a simulation of time handling rather than actual time manipulation as you might do in a software programming language.

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Time Formatting Parsing in VHDL