Re: [PATCH v3 1/5] LoongArch: Fix usage of LSX and LASX frint/ftint instructions [PR112578]

[chenglulu <chenglulu@loongson.cn>]

在 2023/11/24 下午4:26, Xi Ruoyao 写道:
> On Fri, 2023-11-24 at 16:01 +0800, chenglulu wrote:
>> I only saw lrint llrint in n2310 with this description:
>>
>> F7.12.9.5
>>
>> "The lrint and llrint functions round their argument to the nearest
>> integer value, rounding
>> according to the current rounding direction. If the rounded value is
>> outside the range of the return
>> type, the numeric result is unspecified and a domain error or range
>> error may occur."
>>
>> I don't know if I'm right?
> There's an explanation in the linux man-page for lrint:
>
>         SUSv2 and POSIX.1‐2001 contain text about overflow (which might set er‐
>         rno to ERANGE, or raise an FE_OVERFLOW exception).   In  practice,  the
>         result  cannot  overflow on any current machine, so this error‐handling
>         stuff is just nonsense.  (More precisely, overflow can happen only when
>         the maximum value of the exponent is smaller than the  number  of  man‐
>         tissa bits.  For the IEEE‐754 standard 32‐bit and 64‐bit floating‐point
>         numbers  the maximum value of the exponent is 127 (respectively, 1023),
>         and the number of mantissa bits including the implicit bit is  24  (re‐
>         spectively, 53).)
>
This is the description of rint rintf rintl  in the linux man-page.:-(