At 6:15 AM -0800 2/27/07, Geoffrey Broadwell wrote:
What happens when a low-level type overflows or underflows? For
example, if you decrement an int1 twice, what happens?
If you increment a uint8 past 255, do you get:
1. A uint8 with value 0?
2. A uint16 with value 256?
3. A failure?
What about incrementing an int8 past 127? Do you get:
1. An int8 with value -128?
2. A uint8 with value 128?
3. An int16 with value 128?
4. A failure?
In both cases, I think option 1 is best, but I can see that option 2 in
the signed case might make sense in certain circumstances. Personally,
I'd prefer to keep option 1 always, because if I want option 2 I should
cast to uint or a larger int first.
I believe that the answer to this is whatever the underlying
hardware does. These lowercased types are unboxed and directly
reflect their CPU native equivalents, AFAIK. That said, I suspect
that either a wraparound or an overflow code is what you'd get, and
not a type upgrade. -- Darren Duncan
