Re: [Tinycc-devel] The inline assembly clobber for floating point register stack `%st' not implemented?

[Sergey Korshunoff]

My first patch was based on this one. But this patch can not load a
st0 register if "t (x)" constraint is there. And I don't know how to
tell a tcc to do this.



2015-01-21 8:55 GMT+03:00, Roy Tam <address@hidden>:
> Hello,
>
>
> 2015-01-21 1:14 GMT+08:00 Sergey Korshunoff <address@hidden>:
>> There is patch for the win32/include/math.h which removes "t", "st"
>>
>
> I wonder why not just have %t,%st implemented?
> I wrote a small hack for that about half year ago.
> http://lists.gnu.org/archive/html/tinycc-devel/2014-08/msg00024.html
>
>> 2015-01-20 18:25 GMT+03:00, Sergey Korshunoff <address@hidden>:
>>> Because I don't know how to handle a "t" constraint right, a math.h
>>> can be rewritten
>>> like:
>>> long lrint (double x)
>>> {
>>>     long retval;
>>>     __asm__ __volatile__ (
>>>         "fldl   %1\n"
>>>         "fistpl %0\n"  : "=m" (retval) : "m" (x) );
>>>     return retval;
>>> }
>>> insteed of the
>>> long lrint (double x)
>>> {
>>>      long retval;
>>>      __asm__ __volatile__ ("fistpl %0"  : "=m" (retval) : "t" (x) :
>>> "st");
>>>        return retval;
>>> }
>>>
>>> 2015-01-20 17:43 GMT+03:00, Sergey Korshunoff <address@hidden>:
>>>> Handling of the "t" spec needs to be improved. I take patch for it
>>>> from the this mail list (2014)
>>>> tcc don't load a function parameter into the float stack.
>>>> There is asm of the gcc and tcc:
>>>>
>>>> long lrint (double x)
>>>> {
>>>>     long retval;
>>>>     __asm__ __volatile__ ("fistpl %0"  : "=m" (retval) : "t" (x) :
>>>> "st");
>>>>       return retval;
>>>> }
>>>>
>>>> gcc:
>>>>   push   %ebp
>>>>   mov    %esp,%ebp
>>>>   sub    $0x4,%esp
>>>>   fldl      0x8(%ebp)    # !!!
>>>>   fistpl  -0x4(%ebp)
>>>>   mov   -0x4(%ebp),%eax
>>>>   leave
>>>>   ret
>>>>
>>>> tcc:
>>>>   push   %ebp
>>>>   mov    %esp,%ebp
>>>>   sub    $0x4,%esp
>>>>   fistpl -0x4(%ebp)    # where is fldl ???
>>>>   mov  -0x4(%ebp),%eax
>>>>   jmp    14 <lrint+0x14>
>>>>   leave
>>>>   ret
>>>>
>>>
>>
>> _______________________________________________
>> Tinycc-devel mailing list
>> address@hidden
>> https://lists.nongnu.org/mailman/listinfo/tinycc-devel
>>
>
> _______________________________________________
> Tinycc-devel mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/tinycc-devel
>