The trouble with long double

ericflee — Sun, 16 Sep 2007 03:54:00 GMT

Back in ‘04 I made a prediction that 80 bit floating point values would likely be supported in some future version of the VC++ compiler (just like we did in the 16bit version of the compiler!). Alas, it’s now ’07 and much to my disappointment this will not come to pass; so much for my foresight. There are a number of technical reasons for this, not the least of which is that implementing the feature requires more than just a change to the compiler. It is my strong impression, however, that Microsoft would have solved these issues had customers more aggressively clamored for this particular feature.

The point is now rapidly becoming moot. 80-bit doubles seem so “last century”. We are approaching the day when most new Windows systems will have FPUs that easily support the 128bit long double format. It seems natural to expect, or rather for our customers to demand, that 128bit long double semantics be fully supported in some future version of C++.

So lobby away people! http://msdn2.microsoft.com/en-us/visualc/aa336397.aspx

128bit long doubles would be a nice complement to the .NET 128 bit decimal floating point type.

Eric Fleegal's WebLog : VC++ floating-point

The trouble with long double