Another take on decimal data types

[rumbu]

On Sunday, 14 January 2018 at 11:44:39 UTC, kdevel wrote:
> On Sunday, 14 January 2018 at 07:20:26 UTC, rumbu wrote:
>> On Saturday, 13 January 2018 at 22:51:18 UTC, kdevel wrote:
>>> [...]
>>
>> Can you please tell me on your system what are the values for 
>> real.sizeof and real.mant_dig?
>
> They are 12 and 64 (-m32) and 16 and 64 (-m64).
>

This is curious. Because the only documented real type with a 
64-bit mantissa is the 80-bit Intel Extended Precision format 
with a unique sizeof of 10 (and not 12 or 16).

Actually, real80 is the only type I'm supporting in the library, 
any other real type is converted to double. This will explain 
some loss of precision.

Do you have more information about the real type on you system, 
because on mine (Windows), real.sizeof is always 10, irrespective 
of -m32 or -m64.

Mantissa will be easy to extract being 64-bit, but I don't know 
the exact layout of your real type to extract the exponent.