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d2f0ed09f8
The ldbl-128ibm implementation of j0l, j1l, lgammal_r, and cbrtl, as
well as the tables used by expl were copied from ldbl-128. However, the
original files used _Float128 for the type and L() for the literal
suffix. This patch uses the following sed command to rewrite _Float128
as long double and L(x) as xL (for e_expl.c, e_j0l.c, e_j1l.c,
e_lgammal_r.c, and t_expl.h):
sed -i <filename> \
-e "/^#define _Float128 long double/d" \
-e "/^#define L(x) x ## L/d" \
-e "/L(/s/)/L/" \
-e "/L(/s/L(//" \
-e "s/_Float128/long double/g"
For sysdeps/ieee754/ldbl-128ibm/s_cbrtl.c, this sed command incorrectly
replaces a few occurrences of L(), so the following command is used
instead:
sed -i sysdeps/ieee754/ldbl-128ibm/s_cbrtl.c \
-e "/^#define _Float128 long double/d" \
-e "/^#define L(x) x ## L/d" \
-e "s/L(0\.3\{40\})/0.3333333333333333333333333333333333333333L/" \
-e "s/L(3\.7568280825958912391243e-1)/3.7568280825958912391243e-1L/" \
-e "/L(/s/)/L/" \
-e "/L(/s/L(//" \
-e "s/_Float128/long double/g"
Tested for powerpc64le with patched [1] and unpatched gcc.
[1] https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01028.html
* sysdeps/ieee754/ldbl-128ibm/e_expl.c: Remove definitions of
_Float128 and L().
* sysdeps/ieee754/ldbl-128ibm/e_j0l.c: Remove definitions of
_Float128 and L(). Replace _Float128 with long double and L(x)
with xL, throughout the file.
* sysdeps/ieee754/ldbl-128ibm/e_j1l.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/e_lgammal_r.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_cbrtl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/t_expl.h: Likewise.
103 lines
2.7 KiB
C
103 lines
2.7 KiB
C
/* Implementation of cbrtl. IBM Extended Precision version.
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Cephes Math Library Release 2.2: January, 1991
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Copyright 1984, 1991 by Stephen L. Moshier
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Adapted for glibc October, 2001.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* This file was copied from sysdeps/ieee754/ldbl-128/e_j0l.c. */
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#include <math_ldbl_opt.h>
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#include <math.h>
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#include <math_private.h>
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static const long double CBRT2 = 1.259921049894873164767210607278228350570251L;
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static const long double CBRT4 = 1.587401051968199474751705639272308260391493L;
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static const long double CBRT2I = 0.7937005259840997373758528196361541301957467L;
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static const long double CBRT4I = 0.6299605249474365823836053036391141752851257L;
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long double
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__cbrtl (long double x)
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{
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int e, rem, sign;
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long double z;
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if (!isfinite (x))
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return x + x;
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if (x == 0)
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return (x);
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if (x > 0)
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sign = 1;
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else
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{
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sign = -1;
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x = -x;
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}
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z = x;
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/* extract power of 2, leaving mantissa between 0.5 and 1 */
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x = __frexpl (x, &e);
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/* Approximate cube root of number between .5 and 1,
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peak relative error = 1.2e-6 */
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x = ((((1.3584464340920900529734e-1L * x
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- 6.3986917220457538402318e-1L) * x
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+ 1.2875551670318751538055e0L) * x
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- 1.4897083391357284957891e0L) * x
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+ 1.3304961236013647092521e0L) * x + 3.7568280825958912391243e-1L;
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/* exponent divided by 3 */
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if (e >= 0)
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{
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rem = e;
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e /= 3;
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rem -= 3 * e;
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if (rem == 1)
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x *= CBRT2;
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else if (rem == 2)
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x *= CBRT4;
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}
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else
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{ /* argument less than 1 */
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e = -e;
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rem = e;
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e /= 3;
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rem -= 3 * e;
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if (rem == 1)
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x *= CBRT2I;
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else if (rem == 2)
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x *= CBRT4I;
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e = -e;
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}
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/* multiply by power of 2 */
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x = __ldexpl (x, e);
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/* Newton iteration */
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x -= (x - (z / (x * x))) * 0.3333333333333333333333333333333333333333L;
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x -= (x - (z / (x * x))) * 0.3333333333333333333333333333333333333333L;
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x -= (x - (z / (x * x))) * 0.3333333333333333333333333333333333333333L;
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if (sign < 0)
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x = -x;
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return (x);
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}
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long_double_symbol (libm, __cbrtl, cbrtl);
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