[ILAssembly] Can you explain?

Hey I was wondering if any of you know about IL Assembly. I know the basics but I would like to know about compare operations. If\Then\End If in VB.NET or in C# if (something != notthesame) {} else {}

I can call something but I dont know how to react to the function call!!!

Thanks,
PMR

Code:

.method public static void main() cil managed
{
    .entrypoint
    
    ldstr "Can you write in pure IL Assembly Language?"
    call void [mscorlib]System.Console::WriteLine(string)
    
    ldstr "File-C:\\Windows\\Explorer.exe : Exists? : "
    call void [mscorlib]System.Console::Write(string)
    
    ldstr "C:\\Windows\\Explorer.exe" 
    call bool CheckFile(string)
    call void [mscorlib]System.Console::WriteLine(bool)
    
    ret
}

.method public static bool CheckFile(string) cil managed
{
    ldarg.0
    call bool [mscorlib]System.IO.File::Exists(string)
    ret
}

Still a work in progress but i would like to know how to react if CheckFile = False. im going to do a drag and drop super light weight application

EDIT:

is it br [label] or br.s [label]?

 

ok after some messing around I got it!!!

Code:

.method public static void main() cil managed
{
    .locals init([0] string sourceFile, 
    [1] string destFile,
    [2] bool flag
    )
    .entrypoint
    
    ldstr "Can you write in pure IL Assembly Language?"
    call void [mscorlib]System.Console::WriteLine(string)
    
    ldstr "File-D:\\ILCoding\\Exp.exe : Exists? : "
    call void [mscorlib]System.Console::Write(string)
    
    ldstr "D:\\ILCoding\\Exp.exe" 
    stloc.0
    ldloc.0
    
    call bool CheckFile(string)
    stloc.2
    ldloc.2
    
    call void [mscorlib]System.Console::WriteLine(bool)
    
    ldloc.2
    brfalse.s Exit
    
React:

  ldloc.0
  ldstr "D:\\ILCoding\\Exp1.exe"
  stloc.1
  ldloc.1
  ldc.i4.1
  call void [mscorlib]System.IO.File::Copy(string,string,bool)
  br Exit
  
Exit:
  ldstr "Done with your operation..."
  call void [mscorlib]System.Console::WriteLine(string)
  ret
}

.method public static bool CheckFile(string) cil managed
{
    ldarg.0
    call bool [mscorlib]System.IO.File::Exists(string)
    ret
}

that IL Assembly code translates to this in C# and VB.NET

Code:

C#

    public static bool CheckFile(string A_0)
    {
        return File.Exists(A_0);
    }

    public static void main()
    {
        Console.WriteLine("Can you write in pure IL Assembly Language?");
        Console.Write("File-C:\\Windows\\Explorer.exe : Exists? : ");
        string str = "D:\\ILCoding\\Exp.exe";
        bool flag = u003cModuleu003e.CheckFile(str);
        Console.WriteLine(flag);
        if (flag)
        {
            string str1 = "D:\\ILCoding\\Exp1.exe";
            File.Copy(str, str1, true);
        }
        Console.WriteLine("Done with your operation...");
    }

VB.NET

    Public Shared Function CheckFile(ByVal A_0 As String) As Boolean 
        Return File.Exists(A_0)
    End Function

    Public Shared Sub main()
        Console.WriteLine("Can you write in pure IL Assembly Language?")
        Console.Write("File-C:\Windows\Explorer.exe : Exists? : ")
        Dim str As String = "D:\ILCoding\Exp.exe"
        Dim flag As Boolean = u003cModuleu003e.CheckFile(str)
        Console.WriteLine(flag)
        If (flag) Then
            Dim str1 As String = "D:\ILCoding\Exp1.exe"
            File.Copy(str, str1, True)
        End If
        Console.WriteLine("Done with your operation...")
    End Sub

EDIT: I forgot I changed the string around while doing this. It still works but might need to be modded