[PATCH 1/1] fenv support arm

[Joel Sherrill]

Szabolcs, is the code in question compiled with any feature flags set?

I see on Linux that the prototypes would be triggered by _GNU_SOURCE while
in newlib, it is _BSD_SOURCE. Is that possibly contributing?

Can you post a test case? The command line that is failing would also help.

I'd like to not guess at what's wrong.

--joel

On Thu, Jul 2, 2020 at 10:48 AM Joel Sherrill <joel@rtems.org> wrote:

>
>
> On Thu, Jul 2, 2020 at 7:11 AM Szabolcs Nagy <szabolcs.nagy@arm.com>
> wrote:
>
>> The 06/03/2020 23:15, Eshan dhawan via Newlib wrote:
>> > --- /dev/null
>> > +++ b/newlib/libc/machine/arm/sys/fenv.h
>> ...
>> > +#ifndef __ARM_PCS_VFP
>> > +
>> > +int feclearexcept(int excepts);
>> > +int fegetexceptflag(fexcept_t *flagp, int excepts);
>> > +int fesetexceptflag(const fexcept_t *flagp, int excepts);
>> > +int feraiseexcept(int excepts);
>> > +int fetestexcept(int excepts);
>> > +int fegetround(void);
>> > +int fesetround(int round);
>> > +int fegetenv(fenv_t *envp);
>> > +int feholdexcept(fenv_t *envp);
>> > +int fesetenv(const fenv_t *envp);
>> > +int feupdateenv(const fenv_t *envp);
>> > +#if __BSD_VISIBLE
>> > +int feenableexcept(int __mask);
>> > +int fedisableexcept(int __mask);
>> > +int fegetexcept(void);
>> > +#endif /* __BSD_VISIBLE */
>> > +
>> > +#endif       /* __ARM_PCS_VFP */
>>
>> why are these declarations conditional?
>>
>
> The prototypes for the POSIX methods are in the shared fenv.h.
>
> Since the ARM has the BSD_VISIBLE extras, those should be left in the arm
> specific sys/fenv.h.
>
> But (I don't think) they need a ARM_PCS_VFP wrapper since there should be
> an implementation for all multilibs.  We could discuss the BSD_VISIBLE
> prototypes being moved to <fenv.h> and removed from all the architecture
> <sys/fenv.h>
> but that was also how the code I moved from Cygwin to newlib libm was done
> so
> maybe there is a reason that I don't know to leave it here.
>
>>
>> i get build failures e.g. in libgfortran
>> because configure detects the availability
>> of feenableexcept in libm.a so it starts
>> using it but then fenv.h does not have the
>> declaration so compilation fails.
>>
>> it seems there is vfp code for all this
>> so why are the declarations removed?
>>
>
> The FreeBSD headers rely on the architecture sys/fenv.h prototypes
> even for POSIX standard methods. Most of the block of code is removed
> because the prototypes were in <fenv.h> which is where this file is
> included
> from.
>
> Eshan... re-add the BSD_VISIBLE block please and resubmit. It also
> looks like the test code isn't exercising those methods so that should
> be updated after this patch is updated. We don't want libfortran broken
> for longer than neccessary.
>
> --joel
>