>> and << functions for VB

[anhn]

VB does not have >> and << operators but we can create functions to simulate them.
Without unsign data type other than Byte, so we can use only 31 right bits of Long (the largest Long number is 2^31-1).
(Notation "&" below denotes a Long number)

Edit: See New version in post#7

Function RShift(Num as Long, b as Byte) As Long 
'--- Num >> b
   If Num > 0 then
      If b < 31 then
         '-- shift to the right with 0's patched to the left
         RShift = Num \ (2& ^ b)
      Else
         RShift = 0 '-- all bits are shifted away
      End if
   ElseIf Num = 0 then
      RShift = 0
   Else
      '-- can raise an error here
      MsgBox "Num must be >= 0"
   End If
End Function

Function LShift(Num as Long, b as Byte) As Long
'-- Num << b
   If Num > 0 then
      If b = 0 then
         LShift = Num '-- shift nothing
      ElseIf b < 31 then
         '-- Num mod 2&^(31-b) will shift the left-most bits away first to avoid overflow.
         '    * (2& ^ b) will shift the remaining bits to the left 
         '               with 0's patched to the right.
         LShift = (Num mod 2&^(31-b)) * (2& ^ b)
      Else 
         LShift = 0 '-- all bits are shifted away
      End if
   ElseIf Num = 0 then
      LShift = 0
   Else
      '-- can raise an error here
      MsgBox "Num must be >= 0"
   End If
End Function