VBA for 64-bit and 32-bit

Hi,

Below is code that works on 64-bit. I know by switching the LongLong's to Long and removing PtrSafe it works on 32-bit, but I'm wondering how to write this to work on both?

Option Explicit
Private mlngStart As LongLong
Private Declare PtrSafe Function GetTickCount Lib "kernel32" () As LongLong


Public Sub StartTimer()
       mlngStart = GetTickCount
End Sub

Public Function EndTimer() As LongLong
       EndTimer = (GetTickCount - mlngStart)
End Function