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Date: Fri, 11 Apr 2014 11:51:48 -0400
From: Rich Felker <dalias@...ifal.cx>
To: musl@...ts.openwall.com
Subject: Re: Preparing for releases 1.1.0 and 1.0.1

On Fri, Apr 11, 2014 at 11:48:13AM -0400, Rich Felker wrote:
> On Fri, Apr 11, 2014 at 11:17:00AM -0400, Morten Welinder wrote:
> > > Yes but this leads to serious breakage if the compiler does not handle
> > > the request to drop precision in a conforming way, and it still
> > > doesn't help the fact that strtod depends on long double semantics.
> > 
> > Are you sure?
> > 
> > If the incoming number has at most 53 bits then there will be at most
> > 24 bits left after the 2^(1+28) reduction.  The scalings by 10^9 = 2^9 * 5^9
> > require at most log2(5^9) ~ 21 extra bits.
> > 
> > That ought to fit in valgrind's double.
> 
> Are you basing this on a reading of how long double is used in the
> source file, or just generalities? The rounding logic depends on
> exactly how many places are kept/dropped when a certain addition is
> performed.

Maybe we're unclear on what one another are saying. I'm talking about
strtod and family here, not printf.

Rich

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