x86_64: floating-point environment (i.e. fenv.h). BUG.

[Houder]

On 2018-08-01 13:49, Houder wrote:
> On 2018-08-01 13:00, Corinna Vinschen wrote:
>> On Aug  1 12:22, Houder wrote:
>>> Hi Corinna,
>>> 
>>> Short version of my report (as there is more to say about the 
>>> implementation
>>> of
>>> "fenv") in Cygwin; this time I restrict myself to a bug in fegetenv() 
>>> ).
>>> 
>>> (Note to myself: attach STC)
>>> 
>>> I am reporting a bug in fegetenv() in winsup/cygwin/fenv.cc. There is 
>>> no
>>> hurry
>>> in repairing this bug, as "fenv" is hardly ever (never?) used by 
>>> anyone.
>>> 
>>> fegetenv() should be modified as follows:
>>> 
>>> from:
>>>   __asm__ volatile ("fnstenv %0" : "=m" (envp->_fpu) : );
>>>   if (use_sse)
>>>     __asm__ volatile ("stmxcsr %0" : "=m" (envp->_sse_mxcsr) : );
>>>   return 0
>>> 
>>> to:
>>> // Henri: copying glibc ...
>>>   __asm__ volatile ("fnstenv %0\n"
>>>                     "fldenv %0" : "=m" (envp->_fpu) : );
>>>   if (use_sse)
>>>     __asm__ volatile ("stmxcsr %0" : "=m" (envp->_sse_mxcsr) : );
>>>   return 0;
>> 
>> Since you know how to fix things, please just send patches to
>> the cygwin-patches ML.
> 
> Ah ... Agreed. However, as I am not set up for building (anymore), this
> will take some time ... (not even git is installed).
> 
> (yes, I did verify the above modification (and more), however I did 
> that
>  "locally" (basically, I included winsup/cygwin/fenv.cc in my  STC) ).

Corinna,

As requested by you, I made an attempt. See cygwin-patches.

Regards,

Henri

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple