[PATCH v2 2/2] break fenv.c file to function files

Sebastian Huber sebastian.huber at embedded-brains.de
Mon Jul 27 06:30:27 UTC 2020

On 27/07/2020 08:11, Eshan Dhawan wrote:

>>> diff --git a/newlib/libc/machine/arm/sys/fenv.h b/newlib/libc/machine/arm/sys/fenv.h
>>> index 70bd57be4..8712b2f33 100644
>>> --- a/newlib/libc/machine/arm/sys/fenv.h
>>> +++ b/newlib/libc/machine/arm/sys/fenv.h
>>> @@ -62,6 +62,14 @@ typedef int fexcept_t;
>>>   #define    FE_DOWNWARD        0x00800000
>>>   #define    FE_TOWARDZERO        0x00c00000
>>>   +#ifndef __SOFTFP__
>>> +#define    vmrs_fpscr(__r)    __asm __volatile("vmrs %0, fpscr" : "=&r"(__r))
>>> +#define    vmsr_fpscr(__r)    __asm __volatile("vmsr fpscr, %0" : : "r"(__r))
>>> +#define    _FPU_MASK_SHIFT    8
>>> +#define    _ROUND_MASK    (FE_TONEAREST | FE_DOWNWARD | \
>>> +             FE_UPWARD | FE_TOWARDZERO)
>>> +#endif
>>> +
>> I would still prefer to have this in an internal header file "newlib/libm/machine/arm/_fenv.h" which is included via #include "_fenv.h".
>> If you really want to have it visible via <fenv.h>, then the vm*() should at least be renamed to _vmrs_fpscr() and _vmsr_fpscr().
> I am not able to get you point could you provide a little detail
> I understood that you are saying that create an alternative _fenv.h in machine/arm in libm.
> But I am not able to understand why.
> If the symbols are visible with fenv.h than does that cause any issues?

Yes, this is a header file which is included in the C and POSIX 
standards. It should only provide the things covered in the standards. 
The general convention is to reserve all names starting with an 
underscore for the C library implementation and operating system use. 
For example:


> Or how does renaming them causes any change?
It moves the names to the reserved name space.

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