Adding fenv support for ARM

[Eshan Dhawan]

On Wed, May 13, 2020 at 7:40 PM Joel Sherrill <joel at rtems.org> wrote:

> National free hint day!!!
>
> Look above the line that is reported. You will see __BEGIN_DECL. It isn't
> defined. It is intended to expand to the __cplusplus wrapper.
>
> After you fix this, you will sequentially find 2 other things to change in
> this file.
>
> I have made those changes when a new error occurs from the assembler in
arm thumb mode
There is no support for vfp instructions in arm thumb.
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/BABGHDBB.html
So in which file will the compiler instructions given in the page
<http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/BABGHDBB.html>
added?
Errors :

make[9]: Entering directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib/libm/machine/arm'
arm-rtems5-gcc
-B/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib/
-isystem
/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib/targ-include
-isystem /home/eshan/development/newlib/newlib-cygwin/newlib/libc/include
 -mthumb -DPACKAGE_NAME=\"newlib\" -DPACKAGE_TARNAME=\"newlib\"
-DPACKAGE_VERSION=\"3.3.0\" -DPACKAGE_STRING=\"newlib\ 3.3.0\"
-DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -I.
-I../../../../../../../newlib-cygwin/newlib/libm/machine/arm -I
../../../../../../../newlib-cygwin/newlib/libm/machine/arm/../../../../newlib/libm/common
-fno-builtin -mfpu=vfpv2 -ffunction-sections -fdata-sections
 -D_COMPILING_NEWLIB -DCLOCK_PROVIDED -DMALLOC_PROVIDED -DEXIT_PROVIDED
-DSIGNAL_PROVIDED -DGETREENT_PROVIDED -DREENTRANT_SYSCALLS_PROVIDED
-DHAVE_NANOSLEEP -DHAVE_BLKSIZE -DHAVE_FCNTL -DHAVE_ASSERT_FUNC
-D_NO_GETLOGIN -D_NO_GETPWENT -D_NO_GETUT -D_NO_GETPASS -D_NO_SIGSET
-D_NO_WORDEXP -D_NO_POPEN -D_NO_POSIX_SPAWN -DHAVE_INIT_FINI      -g -O2
 -mthumb -c -o lib_a-fenv-vfp.o `test -f 'fenv-vfp.c' || echo
'../../../../../../../newlib-cygwin/newlib/libm/machine/arm/'`fenv-vfp.c
/tmp/ccEHiFws.s: Assembler messages:
/tmp/ccEHiFws.s:37: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:48: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:81: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:119: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:134: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:169: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:182: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:217: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:251: Error: selected processor does not support `vmrs
r0,fpscr' in Thumb mode
/tmp/ccEHiFws.s:288: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:303: Error: selected processor does not support `vmsr
fpscr,r0' in Thumb mode
/tmp/ccEHiFws.s:340: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:374: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:390: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:424: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:457: Error: selected processor does not support `vmrs
r1,fpscr' in Thumb mode
/tmp/ccEHiFws.s:466: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:478: Error: selected processor does not support `vmrs
r2,fpscr' in Thumb mode
/tmp/ccEHiFws.s:503: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:543: Error: selected processor does not support `vmrs
r0,fpscr' in Thumb mode
/tmp/ccEHiFws.s:559: Error: selected processor does not support `vmsr
fpscr,r3' in Thumb mode
/tmp/ccEHiFws.s:595: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
/tmp/ccEHiFws.s:612: Error: selected processor does not support `vmsr
fpscr,r2' in Thumb mode
/tmp/ccEHiFws.s:647: Error: selected processor does not support `vmrs
r3,fpscr' in Thumb mode
Makefile:476: recipe for target 'lib_a-fenv-vfp.o' failed
make[9]: *** [lib_a-fenv-vfp.o] Error 1
make[9]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib/libm/machine/arm'
Makefile:324: recipe for target 'all-recursive' failed
make[8]: *** [all-recursive] Error 1
make[8]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib/libm/machine'
Makefile:553: recipe for target 'all-recursive' failed
make[7]: *** [all-recursive] Error 1
make[7]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib/libm'
Makefile:641: recipe for target 'all-recursive' failed
make[6]: *** [all-recursive] Error 1
make[6]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib'
Makefile:452: recipe for target 'all' failed
make[5]: *** [all] Error 2
make[5]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/thumb/newlib'
Makefile:1260: recipe for target 'multi-do' failed
make[4]: *** [multi-do] Error 1
make[4]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/newlib'
Makefile:1176: recipe for target 'all-multi' failed
make[3]: *** [all-multi] Error 2
make[3]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/newlib'
Makefile:452: recipe for target 'all' failed
make[2]: *** [all] Error 2
make[2]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib/arm-rtems5/newlib'
Makefile:8491: recipe for target 'all-target-newlib' failed
make[1]: *** [all-target-newlib] Error 2
make[1]: Leaving directory
'/home/eshan/development/newlib/c-arm-rtems5-newlib'
Makefile:878: recipe for target 'all' failed
make: *** [all] Error 2

-Eshan

> Then we need to make a decision whether the static inline versions of the
> methods in sys/fenv.h are appropriate for newlib or not.
>
> --joel
>
> On Tue, May 12, 2020 at 5:20 PM Joel Sherrill <joel at rtems.org> wrote:
>
>> 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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