From: Takashi Yano <takashi.yano@nifty.ne.jp>
To: newlib@sourceware.org
Subject: Re: [PATCH] ldtoa: Fix insufficient valid output digits for "%f" format.
Date: Fri, 26 Nov 2021 06:51:06 +0900 [thread overview]
Message-ID: <20211126065106.7f2591edd95b317583a964cc@nifty.ne.jp> (raw)
In-Reply-To: <YZ+ZHZ3jWNwNgePx@calimero.vinschen.de>
On Thu, 25 Nov 2021 15:09:33 +0100
Corinna Vinschen wrote:
> looks good, but I see a potential problem at one point:
>
> On Nov 25 21:02, Takashi Yano wrote:
> > + limit now, either ndec (<= NDEC) or NDEC_SML, depending on ndigits. */
> > + int ndec;
> > + if (mode == 3) /* %f */
> > + {
> > + int expon = (e[NE - 1] & 0x7fff) - (EXONE - 1); /* exponent part */
> > + /* log2(10) approximately 485/146 */
> > + ndec = expon * 146 / 485 + ndigits;
>
> We have targets with sizeof(int) == 2. If expon is any number up to
> 0x7fff, multiplying it with 146 will overflow. Using __int32_t for
> expon should be safer.
Thanks for checking. I have just submitted v2 patch fixed.
--
Takashi Yano <takashi.yano@nifty.ne.jp>
prev parent reply other threads:[~2021-11-25 21:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-25 12:02 Takashi Yano
2021-11-25 14:09 ` Corinna Vinschen
2021-11-25 21:51 ` Takashi Yano [this message]
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