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/* See the import.pl script for potential modifications */
/* Compute cubic root of Simple value.
Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Dirk Alboth <dirka@uni-paderborn.de> and
Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1f of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include "SMath.h"
#include "math_private.h"
#define CBRT2 1.2599210498948731648f /* 2^(1/3) */
#define SQR_CBRT2 1.5874010519681994748f /* 2^(2/3) */
static const Simple factor[5] =
{
1.0f / SQR_CBRT2,
1.0f / CBRT2,
1.0f,
CBRT2,
SQR_CBRT2
};
namespace streflop_libm {
Simple
__cbrtf (Simple x)
{
Simple xm, ym, u, t2;
int xe;
/* Reduce X. XM now is an range 1.0f to 0.5f. */
xm = __frexpf (fabsf (x), &xe);
/* If X is not finite or is null return it (with raising exceptions
if necessary.
Note: *Our* version of `frexp' sets XE to zero if the argument is
Inf or NaN. This is not portable but faster. */
if (xe == 0 && fpclassify (x) <= FP_ZERO)
return x + x;
u = (0.492659620528969547f + (0.697570460207922770f
- 0.191502161678719066f * xm) * xm);
t2 = u * u * u;
ym = u * (t2 + 2.0f * xm) / (2.0f * t2 + xm) * factor[2 + xe % 3];
return __ldexpf (x > 0.0f ? ym : -ym, xe / 3);
}
weak_alias (__cbrtf, cbrtf)
}
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