Convert minimum integer value of signed type to half

[Rui Wang]

Hi,

Thank you for making this library, it really helps a lot in my work.

But recently, I have found that when I use half_cast() to convert the minimum value of short type (-32768) to half, I get -1, but it should be -32768. This problem also occurs when converting the minimum value of int type. I'm not sure, but it may be related to the overflow in half. hpp: 1082 line, or did I miss something?

The following code can reproduce this issue.

short x = std::numeric_limits<short>::min();
std::cout << x << '\n';    //  -32768
std::cout << half_float::half_cast<half_float::half>(x) << '\n'; //    -1

[Christian Rau]

Yes, there is indeed a bug in the integer to half conversion when calling it with the type's minimum negative value, since on two's complement platforms (which is virtually everywhere) that doesn't have a positive equivalent inside the type's own domain. I will look into fixing it.

Thank you for bringing this up.