Doing math with unsigned 32bit

I have an Int Ptr which is pointing to some 32-bit image data in memory, which holds an unsigned 32-bit number (not rgb, just 32-bit components). Normally Int's are signed.

I want to read this unsigned number in and do math with the correct unsigned value.

If I do this:

Local MyIntPtr:Int Ptr=BasePtr+Xpos+(Ypos*PixelsPerRow)
Local a:Long=Long(MyIntPtr[0])

and if the value being read is more than 2^31-1, surely it will read it as some negative number, and then when casting it as a Long it will just make it a long version of that negative number, rather than preserve the unsigned value?

How can I read the Int, and only the Int (without having to read a Long from memory), and get the unsigned value into a Long?

I guess I answered it myself:

With this:

Local a:Int=$FEDCBA98
Local b:Int Ptr=Int Ptr(Varptr(a))
Local c:Long=Long(b[0])
Print "Was $FEDCBA98"
Print "Is "+Hex$(c Shr 32)+Hex$(c & $FFFFFFFF)

produces:

Was $FEDCBA98
Is 00000000FEDCBA98

So the answer is, Long() doesn't INTERPRET the value, it just converts it from a 32-bit variable into a 64-bit variable and copies over the BITS, not the interpreted value of the bit.

Which is good ;-)