There are no current plans to add 80 bit FP support.
The major reason is that FP code generation has been switching to the use of SSE/SSE2/SSE3 instruction sets instead of the x87 FP stack since that is what both the AMD and Intel recent and future chip generations are focusing their performance efforts on. These instruction sets only support 32 and 64 bit FP formats.
Acting Product Unit Manager
Visual C++ Team
Yes, just like long and int are distinct types although they happen to map to the same machine type on both 32 and 64 bit Windows platforms.
Doing it differently would hurt cross platform portability of C++ code now and would make it harder to cleanly support extended precision in the future if and when it becomes critical (say if HW architectures commonly support 128 bit FP types and algorithms that require that precision become relevant).
Re: [RESOLVED] When is 80bit long double coming back?
I don't think legacy support for the exotic 80-bit floating point makes any sense.
However, I would love to see...
- Native compiler support for 128-bit floating point representations in C/C++.
- As well as native compiler support INT128 / UINT128 in C / C++.
The SSE2 instruction coding for the integer operations is rather straight forward.
However the 128-bit floating point is difficult to specify and much more difficult to implement in <cmath>. However it's not as bad as you might think once you've got the FP representation and the basic add / sub / mul / div.
Any plans here.
You're gonna go blind staring into that box all day.