Well, I got the big idea that I'd convert my
Tiny Abstract OS in C#
to other languages (VB.NET, J#, etc) and platforms (
.NET CF
,
Mono
). I figured it'd be a good exercise to practice VB.NET since it's
moderately
complex and
moderately
OOP. I've never been one who can bang out little samples - I really need something cohesive and meaty if I'm going to really dig into it. Plus, it'd be cool to have other versions of the TinyOS around in other languages. It really exercises the basics of the .NET Framework, and it's been downloaded 4955 times from
http://www.gotdotnet.com
, which is very exciting and I get mail about it all the time.
So, I figured I'd start with VB.NET before I fire up VMWare and my Mono VM. I sat down and started using the C# to VB.NET converter VS.NET Add-In. I converted the who project and received 102 Todos, which is about more than I expected. I had no idea what was really going on...until I saw things like this in my new VB Project:
If
instr.Param2 <> System.UInt32.MaxValue
Then
'ToDo: Unsigned Integers not supported
Public
Sub
New
(id
As
System.UInt32, memorySize
As
System.UInt32)
'ToDo: Unsigned Integers not supported
'ToDo: Unsigned Integers not supported
pid = id
registers(8) =
CType
(pid, System.UInt32)
'ToDo: Unsigned Integers not supported
processMemorySize = memorySize
End
Sub
'New
Turns out, from a
CLS
point of view, I really shot myself in the foot on this one. I wrote this Tiny OS using exactly what I needed - when the system called for UInt32, I used one. Apparently (I knew this, but never really
grokked
it) the CLS does not define an unsigned integer, and the
UInt32
type is marked as not CLS compliant. So, what type should I use? It was a silly thing really, to build something low-level bits-and-bytes with a managed language, but since I was at a low level, it seemed silly to only use the signed half of an Integer.
Well, I'm going to re-think this little exercise, perhaps I'll first try to get it running as a C# app in Mono and go from there.
Let me add one particuar point of note. I'm interested in this valiant attempt by the C# to VB.NET Converter and appreciate any insights. When trying to convert this particularly icky (
hacky...now that I look at it, I could have done it easier with adding the bytes and shifting bits as I added...ah, how
time refactors for you...
) bit of C# code:
public
unsafe
static
uint
BytesToUInt(
byte
[] BytesIn)
{
fixed
(
byte
* otherbytes = BytesIn)
{
uint
newUint = 0;
uint
* ut = (
uint
*)&otherbytes[0];
newUint = *ut;
return
newUint;
}
}
The C# to VB.NET converter came up with this:
Private
Declare
Sub
CopySystem.UInt32
Lib
"Kernel32.dll"
Alias
"RtlMoveMemory" (
ByRef
Destination
As
System.UInt32,
ByRef
Source
As
System.UInt32, ByteCount
As
Integer
)
Public
Shared
Function
BytesToUInt(BytesIn()
As
Byte
)
As
System.UInt32
'ToDo: Unsigned Integers not supported
Dim
otherbytes
As
Machine.BytePtr =
New
Machine.BytePtr(BytesIn)
Try
Dim
newUint
As
System.UInt32 = 0
'ToDo: Unsigned Integers not supported
Dim
ut
As
Machine.TypePtr =
New
Machine.TypePtr(Machine.TypePtr.Cast(Machine.NewPointer(otherbytes(0)),
GetType
(System.UInt32)),
typeof
(System.UInt32))
'ToDo: Unsigned Integers not supported
CopySystem.UInt32(newUint, ut.Address, Runtime.InteropServices.Marshal.SizeOf(
GetType
(System.UInt32)))
Return
newUint
Finally
otherbytes.Dispose()
End
Try
End
Function
'BytesToUInt
Hmm...
