On Friday, 18 May 2012 at 19:59:01 UTC, Paul D. Anderson wrote:
On Sunday, 6 May 2012 at 16:27:34 UTC, Alex Rønne Petersen
wrote:
On 05-05-2012 06:57, Alex Rønne Petersen wrote:
Hi,
I don't think the language really makes it clear whether
overflows and
underflows are well-defined. Do we guarantee that for any
integral type
T, T.max + 1 == T.min and T.min - 1 == T.max?
This is relevant in particular for GDC and LDC since they
target a lot
of weird architectures.
Can anyone give a definitive answer to this or at least
confirm that it is an open issue?
I don't have the reference at the moment but the C99(?)
standard requires wraparound behavior by UNSIGNED integer
values. I don't know if there is an equivalent requirement for
signed values.
Sorry, it's C++:
3.9.1/4
Unsigned integers, declared unsigned, shall obey the laws of
arithmetic modulo 2n where n is the number of bits in the value
representation of that particular size of integer.
Paul
