Re: [PATCH] Fix expf overflow limit

[Corinna Vinschen <vinschen@redhat.com>]

On Feb  9 14:52, Andoni Arregi wrote:
> Correct the overflow limit in the variable o_threshold to be consistent
> with the FLT_UWORD_LOG_MAX variable used by the internal implementation
> of the expf algorithm itself.
> The u_threshold variable has also been modified to be written in the
> same format.
> 
> Note that this fix improves the situation but does not completely
> correct the inconsistencies regarding the overflow and underflow limits
> between the expf wrapper (wf_exp.c) and the expf algorithm itself
> (ef_exp.c).
> 
> Currently these limits are different for the
> _FLT_LARGEST_EXPONENT_IS_NORMAL and _FLT_NO_DENORMALS cases as well as
> for the case where __OBSOLETE_MATH is not defined (only for the
> underflow limit in this case).
> ---
>  newlib/libm/math/wf_exp.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/newlib/libm/math/wf_exp.c b/newlib/libm/math/wf_exp.c
> index 38cacd95a..075b5bb0a 100644
> --- a/newlib/libm/math/wf_exp.c
> +++ b/newlib/libm/math/wf_exp.c
> @@ -26,8 +26,8 @@ static const float
>  #else
>  static float
>  #endif
> -o_threshold=  8.8721679688e+01,  /* 0x42b17180 */
> -u_threshold= -1.0397208405e+02;  /* 0xc2cff1b5 */
> +o_threshold=  0x1.62e42ep+06,  /* 0x42b17217 */
> +u_threshold= -0x1.9fe36ap+06;  /* 0xc2cff1b5 */
>  
>  #ifdef __STDC__
>  	float expf(float x)		/* wrapper expf */
> -- 
> 2.35.1

Pushed.


Thanks,
Corinna