glibc/sysdeps/ieee754/ldbl-96/s_cbrtl.c
Ulrich Drepper 1f5649f86b Update.
2001-10-14  Ulrich Drepper  <drepper@redhat.com>

	* locale/programs/ld-collate.c (handle_ellipsis): Use %lX not %lx
	to generate hexadecimal identifier.
	Patch by Jungshik Shin <jungshik.shin@yale.edu>.

2001-10-09  Stephen L Moshier  <moshier@mediaone.net>

	* sysdeps/ieee754/ldbl-96/s_cbrtl.c (__cbrtl): Fix algorithm.

2001-10-14  Ulrich Drepper  <drepper@redhat.com>

	* sysdeps/ieee754/ldbl-128/e_powl.c: New file.
	* sysdeps/ieee754/ldbl-128/s_cbrtl.c: New file.
	Contributed by Stephen L Moshier <moshier@mediaone.net>.

	* sysdeps/ieee754/ldbl-128/e_j0l.c: Constify float variables.
	* sysdeps/ieee754/ldbl-128/e_j1l.c: Likewise.
	* sysdeps/ieee754/ldbl-128/e_lgammal_r.c: Likewise
	* sysdeps/ieee754/ldbl-128/s_erfl.c: Likewise
	* sysdeps/ieee754/ldbl-128/s_expm1l.c: Likewise
	* sysdeps/ieee754/ldbl-128/s_log1pl.c: Likewise

	* timezone/africa: Update from tzdata2001d.
	* timezone/asia: Likewise.
	* timezone/australasia: Likewise.
	* timezone/backward: Likewise.
	* timezone/europe: Likewise.
	* timezone/leapseconds: Likewise.
	* timezone/northamerica: Likewise.
	* timezone/southamerica: Likewise.
	* timezone/zone.tab: Likewise.

2001-10-09  Martin Schwidefsky  <schwidefsky@de.ibm.com>

	* sysdeps/s390/s390-32/sys/ucontext.h: Correct __psw_t typedef.
	* sysdeps/s390/s390-64/sys/ucontext.h: Likewise.
2001-10-14 22:33:08 +00:00

72 lines
2.2 KiB
C

/* Compute cubic root of double 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 2.1 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 "math.h"
#include "math_private.h"
#define CBRT2 1.2599210498948731648 /* 2^(1/3) */
#define SQR_CBRT2 1.5874010519681994748 /* 2^(2/3) */
/* We don't use long double values here since U need not be computed
with full precision. */
static const double factor[5] =
{
1.0 / SQR_CBRT2,
1.0 / CBRT2,
1.0,
CBRT2,
SQR_CBRT2
};
static const long double third = 0.3333333333333333333333333L;
long double
__cbrtl (long double x)
{
long double xm, u;
int xe;
/* Reduce X. XM now is an range 1.0 to 0.5. */
xm = __frexpl (fabs (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 = (((-1.34661104733595206551E-1 * xm
+ 5.46646013663955245034E-1) * xm
- 9.54382247715094465250E-1) * xm
+ 1.13999833547172932737E0) * xm
+ 4.02389795645447521269E-1;
u *= factor[2 + xe % 3];
u = __ldexpl (x > 0.0 ? u : -u, xe / 3);
u -= (u - (x / (u * u))) * third;
u -= (u - (x / (u * u))) * third;
return u;
}
weak_alias (__cbrtl, cbrtl)