Is real(16) available on x86 platforms?

[Tim Prince]

Erik Schnetter wrote:
> On Jan 14, 2007, at 10:16:12, Dominique Dhumieres wrote:
>
>>> Your question is sort of wrong.
>>
>> OK! Is 128-bit floating point type supported on AMD64
>> running the FX's x86_64-unknown-linux-gnu?
>>
>> More precisely, I was trying to test a piece of code using
>> real(16) executing (not working) on a G5 under OSX 10.3 (PPC)
>> on an AMD64 box under linux where I got the error.
>>
>> I was a bit surprised because as far as a know real(16) floats
>> are not supported by the G5 hardware, but a some software
>> emulation (gmp/mpfr?). I was just expecting the same for AMD64,
>> why shouldn't it be?
>
> I think real(16) is implemented on PPC by combining two real(8) 
> numbers suitably.  That is slower than a hardware-supported 
> implementation, but gives you the accuracy.
>
Not as much accuracy or range as IEEE standard requires for 128-bit 
format. More precision but less range than real(10).  You could call it 
a hardware-supported implementation, as it takes advantage of the 
characteristics of fused multiply-add.