Convert Visual Basic function to PHP Code

I need someone to convert this code which, is a visual basic function, to a php function. It must produce an identical value as the visual basic counterpart. I can explain the process more in detail as far as the visual basic side goes. Public Function GenRegCode(UserName As String, Password As String) As String Dim CharNum As Long, PassChar As Long, RegCode As String, TmpStr As String, ProcessHex As String, ScrambleOrd As Long PassChar = 1 TmpStr = "" RegCode = "" UserName = UCase(UserName) Password = UCase(Password) For CharNum = 1 To Len(UserName) ProcessHex = Hex(Asc(Mid(UserName, CharNum, 1)) Xor Asc(Mid(Password, PassChar, 1))) If Len(ProcessHex) Len(Password) Then PassChar = 1 Next CharNum Do Until Len(RegCode) = Len(TmpStr) ScrambleOrd = ScrambleOrd + 1 RegCode = RegCode & Mid(TmpStr, ScrambleOrd * 2, 1) & Mid(TmpStr, ScrambleOrd * 2 - 1, 1) Loop GenRegCode = RegCode End Function