On Apr 20, 2011, at 5:06 AM, Don wrote:
> Sean Kelly wrote:
>> On Apr 16, 2011, at 1:02 PM, Robert Jacques wrote:
>>> On Sat, 16 Apr 2011 15:32:12 -0400, Walter Bright
>>> <newshou...@digitalmars.com> wrote:
>>>>
>>>> The dmd startup code (actually the C startup code) does an fninit. I never
>>>> thought about new thread starts. So, yeah, druntime should do an fninit on
>>>> thread creation.
>>> The documentation I've found on fninit seems to indicate it defaults to
>>> 64-bit precision, which means that by default we aren't seeing the benefit
>>> of D's reals. I'd much prefer 80-bit precision by default.
>> There is no option to set "80-bit precision" via the FPU control word.
>
> ??? Yes there is.
>
> enum PrecisionControl : short {
> PRECISION80 = 0x300,
> PRECISION64 = 0x200,
> PRECISION32 = 0x000
> };
So has Intel deprecated 80-bit FPU support? Why do the docs for this say that
64-bit is the highest precision? And more importantly, does this mean that we
should be setting the PC field explicitly instead of relying on fninit? The
docs say that fninit initializes to 64-bit precision. Or is that inaccurate as
well?
