On 7 April 2014 15:56, Avi Kivity <a...@cloudius-systems.com> wrote: > On 04/06/2014 01:18 PM, Peter Maydell wrote: >> The alternative would be to say that Int128 should have >> undefined behaviour on underflow/overflow and the test >> code is wrong, but that doesn't seem very useful to me.
> Isn't the test broken here? It is trying to add (or shift) -2^127 and > something else, and the result truly overflows. Well, the test code is assuming "semantics as per 2s complement arithmetic" and checking various corner cases. As I say, we could define that this is invalid and rewrite the test cases. thanks -- PMM