Dear Squeakers,
I have changed my mind a little bit after studying some Squeak sources.
Now I plan to implement LargeInteger primitives (20-39) _without_ changing the representation of LargeIntegers by extending the Interpreter arithmetic primitives using the CCodeGenerator. This avoids some problems dealing with different platforms.
In a later step changing the representation to bigger 'digits' (16,32,.. bits?) _could_ be interesting.
Perhaps 16 bits, but unlikely 32. How, for example, would you handle integer overflow when doing, say, the LargeInteger add? And how could you do the multiply without bit munging? Is it possible that a straight loop with carry would be much faster than all the masking and shifting necessary to do a carry written in C?