> I have sought but not found unsigned comparisons on the integer types
> int32, int64, and nativeint.  I especially need `unsigned less than'.
> Where might I find bindings for these operations?

In a pinch, you can always use signed compares after shifting the
arguments by min_int, e.g.:

let ule_int32 a b = Int32.add a Int32.min_int <= Int32.add b Int32.min_int

(I have a very strong feeling that it should work, but no doubt
expert bit-twiddlers on this list will correct me if it doesn't.)

The code generated for this is nowhere as efficient as a
processor-native unsigned comparison, though.  

- Xavier Leroy