Adding fenv support for ARM

[Joel Sherrill]

Gedare is right but one more piece of information is needed. When newlib is
being built, it lays target dependent files on top of generic ones. So the
default sys/fenv.h is replaced with something like
libc/machine/arm/sys/fenv.h. Make sure that
/home/eshan/development/newlib/newlib-cygwin/newlib/libc/include/fenv.h is
in fact the file you think it should be.

Also look at what is supposed to be in the generic fenv.h and <sys/fenv.h>.
You will probably have to tweak it some.

Check out what is in x86_64/fenv.h and riscv/fenv.h with respect to the
default environment variable. It looks to be declared differently in the
other ports so you may have to make it match.

But more output does help.

--joel



On Tue, May 12, 2020 at 4:53 PM Gedare Bloom <gedare at rtems.org> wrote:

> Take the first error reported, and show what is being compiled. You've
> trimmed off too much preceding this to know what is being compiled and
> how this might be influencing your error.
>
> The specific error you're getting is often due to some syntax errors
> preceding the line shown.
>
> On Tue, May 12, 2020 at 2:59 PM Eshan Dhawan <eshandhawan51 at gmail.com>
> wrote:
> >
> > Hello everyone,
> > After adding the files and compiling. I am
> > getting a few errors which I am not able to rectify.
> > If you could take a look and tell how to sort them.
> >
> > link to newlib's git repo:
> https://github.com/eshandhawan51/newlib-cygwin/tree/add_fenv_support
> >
> > errors :
> >
> > In file included from
> /home/eshan/development/newlib/newlib-cygwin/newlib/libc/include/fenv.h:15:0,
> >                  from
> ../../../../../../newlib-cygwin/newlib/libm/fenv/feclearexcept.c:57:
> >
> /home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib/targ-include/sys/fenv.h:82:1:
> error: expected '=', ',', ';', 'asm' or '__attribute__' before 'extern'
> >  extern const fenv_t *_fe_dfl_env;
> >  ^~~~~~
> > In file included from
> ../../../../../../newlib-cygwin/newlib/libm/fenv/feclearexcept.c:57:0:
> >
> /home/eshan/development/newlib/newlib-cygwin/newlib/libc/include/fenv.h:22:1:
> error: expected '=', ',', ';', 'asm' or '__attribute__' before 'int'
> >  int feclearexcept(int excepts);
> >  ^~~
> >
> > thanks
> > -Eshan
> > On Sat, May 9, 2020 at 2:53 AM Joel Sherrill <joel at rtems.org> wrote:
> >>
> >>
> >>
> >> On Thu, May 7, 2020 at 1:33 PM Eshan Dhawan <eshandhawan51 at gmail.com>
> wrote:
> >>>
> >>> Hello everyone,
> >>> This the tread to discuss adding fenv support for ARM architecture in
> newlib.
> >>>
> >>> Link to previous thread:
> https://lists.rtems.org/pipermail/devel/2020-March/058473.html
> >>>
> >>> ---FreeBSD Source
> >>> # https://github.com/freebsd/freebsd/tree/master/lib/msun/arm
> >>> #
> https://github.com/freebsd/freebsd/blob/master/sys/arm/include/ieeefp.h
> >>> ---NetBSD Source
> >>> # https://github.com/NetBSD/src/tree/trunk/lib/libm/arch/arm
> >>>
> >>> --- Musl has no implementation for fenv support for ARM  in it
> >>>
> >>> After going through the implementations both FreeBSD and NetBSD have a
> stub implementation.
> >>> But then FreeBSD implementation seems to be more portable compared to
> that in NetBSD.
> >>>
> >>> Should I start porting it from FreeBSD?
> >>> And which ARM BSP should I use for testing the changes?
> >>> Currently, I have xilinx_zynq_a9_qemu build
> >>
> >>
> >> I think the FreeBSD implementation is the one to use. It looks to
> support hard and soft floating point implementations.
> >>
> >> I think the fenv.h file there will have to be worked on so some of the
> contents go into sys or machine/fenv.h. There is a portable fenv.h.
> >>
> >>>
> >>>
> >>> There would also be a requirement to discuss where to place the files
> in Newlib.
> >>
> >>
> >> Not much to discuss. It should go into
> newlib-cygwin/newlib/libm/machine/arm.
> >>>
> >>>
> >>> Thanks
> >>> -Eshan
> >>>
> > _______________________________________________
> > devel mailing list
> > devel at rtems.org
> > http://lists.rtems.org/mailman/listinfo/devel
>
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