From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com, Petr Hosek <phosek@chromium.org>
Subject: Re: [PATCH] math: fix expf(-NAN) to return -NAN instead of 0
Date: Fri, 4 Mar 2016 22:40:31 +0100 [thread overview]
Message-ID: <20160304214031.GN29662@port70.net> (raw)
In-Reply-To: <20160304213753.GM29662@port70.net>
* Szabolcs Nagy <nsz@port70.net> [2016-03-04 22:37:53 +0100]:
> expf(-NAN) was treated as expf(-large) which unconditionally
> returns +0, so special case +-NAN.
>
> reported by Petr Hosek.
> ---
> src/math/expf.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/src/math/expf.c b/src/math/expf.c
> index 16e9afe..4a742e4 100644
> --- a/src/math/expf.c
> +++ b/src/math/expf.c
> @@ -39,6 +39,8 @@ float expf(float x)
>
> /* special cases */
> if (hx >= 0x42aeac50) { /* if |x| >= -87.33655f or NaN */
in the comment -87... should be 87...
but i didnt want to include that into the bug fix
> + if (hx > 0x7f800000) /* +-NaN */
> + return x;
> if (hx >= 0x42b17218 && !sign) { /* x >= 88.722839f */
> /* overflow */
> x *= 0x1p127f;
> --
> 2.7.0
next prev parent reply other threads:[~2016-03-04 21:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-04 21:37 Szabolcs Nagy
2016-03-04 21:40 ` Szabolcs Nagy [this message]
2016-03-04 22:06 ` Szabolcs Nagy
2016-03-06 0:59 ` Rich Felker
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