GDC release 0.23

[Anders F Björklund]

Sean Kelly wrote:

> That reminds me.  Is it really a good idea to map the GCC/PPC "long 
> double" to "real" in D?  I know this has come up before:
> 
> http://www.digitalmars.com/d/archives/digitalmars/D/20790.html

No, it's not a good idea to do this on the PowerPC, if the
-mlong-double-128 option is used. (i.e. instead of 64 bits)
I haven't checked what the default ABI is on later versions,
but I'm afraid that "double double" might be the default now...

Staying clear of the "real" type on non-X86 sounds like an idea.

> I can't claim to have the maths background of some folks here, but this 
> suggests to me that this 128-bit representation isn't truly IEEE-754 
> compliant and therefore probably shouldn't be a default data type in D?

The D definition of real as the "largest hardware supported type"
indicates that it should be defined as double on PowerPC (32/64).
At least until there is some kind of new model that does 128-bit
floating point in hardware, instead of faking it with two 64-bit.

I think that things would have been better with an 80-bit D type.

--anders