GDC/ARM: Help needed: Porting std.math.internal.gammafunction

[John Colvin via Digitalmars-d]

On Thursday, 3 July 2014 at 17:54:17 UTC, John Colvin wrote:
> On Thursday, 3 July 2014 at 15:35:35 UTC, Johannes Pfau wrote:
>> Hi,
>>
>> std.math.internal.gammafunction is the last module with failing
>> unittest on ARM, simply because it assumes that reals are 
>> always in
>> x86 extended precision format which is obviously not true on 
>> ARM.
>>
>> I haven't got the required (maths) knowledge to fix this, so 
>> it'd be
>> very appreciated if somebody could take a look.
>>
>> It's actually possible to easily test this on x86 with gdc: 
>> Just install
>> a recent gdc build and use the -mlong-double-64 command line 
>> argument.
>> More details and bug report here:
>>
>> https://issues.dlang.org/show_bug.cgi?id=13032
>
> some trial and error suggests that gammaStirling needs it's 
> threshold changing from 1024.0L to 143.0L when using 64bit 
> reals to avoid overflow.

MAXGAMMA will also need changing. I don't think there's anything 
else wrong with gamma and gammaStirling, I haven't looked at the 
others yet.