Bug#237373: libc6-dev: support for fegetprec / fesetprec to control the dynamic precision modes
At Thu, 11 Mar 2004 11:19:15 +0100,
Vincent Lefevre wrote:
> The WG14 N752 C9X revision proposal contained functions for
> controlling the dynamic precision modes:
>
> The fegetprec and fesetprec functions provide control of
> dynamic precision modes.
>
> Each macro
>
> FE_FLTPREC
> FE_DBLPREC
> FE_LDBLPREC
>
> is defined if and only if the implementation supports the
> dynamic precision by means of the functions in 7.6.z. The
> defined macros expand to integral constant expressions whose
> values are distinct.
>
> You can see http://anubis.dkuug.dk/jtc1/sc22/wg14/www/docs/n752.htm
> for more information. Unfortunately, this was dropped. But some
> vendors implement them anyway. I'd like them to be implemented in
> glibc too. If these functions and macros became a de facto standard,
> this would be very useful when one wants double-precision rounding
> on x86 processors. The problem with fpu_control.h features is that
> they are specific to glibc.
Could you provide me more information?
- Which merit should we use them?
- n752.htm has only above explanation. Where can I get more info?
- Do x86 processors have this kind of functions?
- Why was this dropped?
Regards,
-- gotom
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