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Re: Fix e_logl (128ibm) spurious underflow
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: Richard Henderson <rth at twiddle dot net>
- Cc: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>, "GNU C. Library"<libc-alpha at sourceware dot org>
- Date: Wed, 27 Feb 2013 23:51:33 +0000
- Subject: Re: Fix e_logl (128ibm) spurious underflow
- References: <512E686B.9040007@linux.vnet.ibm.com> <512E977E.1010508@twiddle.net>
On Wed, 27 Feb 2013, Richard Henderson wrote:
> On 2013-02-27 12:11, Adhemerval Zanella wrote:
> > +static const long double
> > + ldbl_epsilon = 0x1p-106L;
> > +
>
> Can't you use the <float.h> constant LDBL_EPSILON?
The semantics of LDBL_EPSILON for IBM long double (the least positive
subnormal double value, because of the discontiguous mantissa bits) are
wrong for uses such as this.
--
Joseph S. Myers
joseph@codesourcery.com