diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-96/e_gammal_r.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-96/e_gammal_r.c | 210 |
1 files changed, 0 insertions, 210 deletions
diff --git a/sysdeps/ieee754/ldbl-96/e_gammal_r.c b/sysdeps/ieee754/ldbl-96/e_gammal_r.c deleted file mode 100644 index 7e42cc1161..0000000000 --- a/sysdeps/ieee754/ldbl-96/e_gammal_r.c +++ /dev/null @@ -1,210 +0,0 @@ -/* Implementation of gamma function according to ISO C. - Copyright (C) 1997-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by 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, see - <http://www.gnu.org/licenses/>. */ - -#include <math.h> -#include <math_private.h> -#include <float.h> - -/* Coefficients B_2k / 2k(2k-1) of x^-(2k-1) inside exp in Stirling's - approximation to gamma function. */ - -static const long double gamma_coeff[] = - { - 0x1.5555555555555556p-4L, - -0xb.60b60b60b60b60bp-12L, - 0x3.4034034034034034p-12L, - -0x2.7027027027027028p-12L, - 0x3.72a3c5631fe46aep-12L, - -0x7.daac36664f1f208p-12L, - 0x1.a41a41a41a41a41ap-8L, - -0x7.90a1b2c3d4e5f708p-8L, - }; - -#define NCOEFF (sizeof (gamma_coeff) / sizeof (gamma_coeff[0])) - -/* Return gamma (X), for positive X less than 1766, in the form R * - 2^(*EXP2_ADJ), where R is the return value and *EXP2_ADJ is set to - avoid overflow or underflow in intermediate calculations. */ - -static long double -gammal_positive (long double x, int *exp2_adj) -{ - int local_signgam; - if (x < 0.5L) - { - *exp2_adj = 0; - return __ieee754_expl (__ieee754_lgammal_r (x + 1, &local_signgam)) / x; - } - else if (x <= 1.5L) - { - *exp2_adj = 0; - return __ieee754_expl (__ieee754_lgammal_r (x, &local_signgam)); - } - else if (x < 7.5L) - { - /* Adjust into the range for using exp (lgamma). */ - *exp2_adj = 0; - long double n = __ceill (x - 1.5L); - long double x_adj = x - n; - long double eps; - long double prod = __gamma_productl (x_adj, 0, n, &eps); - return (__ieee754_expl (__ieee754_lgammal_r (x_adj, &local_signgam)) - * prod * (1.0L + eps)); - } - else - { - long double eps = 0; - long double x_eps = 0; - long double x_adj = x; - long double prod = 1; - if (x < 13.0L) - { - /* Adjust into the range for applying Stirling's - approximation. */ - long double n = __ceill (13.0L - x); - x_adj = x + n; - x_eps = (x - (x_adj - n)); - prod = __gamma_productl (x_adj - n, x_eps, n, &eps); - } - /* The result is now gamma (X_ADJ + X_EPS) / (PROD * (1 + EPS)). - Compute gamma (X_ADJ + X_EPS) using Stirling's approximation, - starting by computing pow (X_ADJ, X_ADJ) with a power of 2 - factored out. */ - long double exp_adj = -eps; - long double x_adj_int = __roundl (x_adj); - long double x_adj_frac = x_adj - x_adj_int; - int x_adj_log2; - long double x_adj_mant = __frexpl (x_adj, &x_adj_log2); - if (x_adj_mant < M_SQRT1_2l) - { - x_adj_log2--; - x_adj_mant *= 2.0L; - } - *exp2_adj = x_adj_log2 * (int) x_adj_int; - long double ret = (__ieee754_powl (x_adj_mant, x_adj) - * __ieee754_exp2l (x_adj_log2 * x_adj_frac) - * __ieee754_expl (-x_adj) - * __ieee754_sqrtl (2 * M_PIl / x_adj) - / prod); - exp_adj += x_eps * __ieee754_logl (x_adj); - long double bsum = gamma_coeff[NCOEFF - 1]; - long double x_adj2 = x_adj * x_adj; - for (size_t i = 1; i <= NCOEFF - 1; i++) - bsum = bsum / x_adj2 + gamma_coeff[NCOEFF - 1 - i]; - exp_adj += bsum / x_adj; - return ret + ret * __expm1l (exp_adj); - } -} - -long double -__ieee754_gammal_r (long double x, int *signgamp) -{ - u_int32_t es, hx, lx; - long double ret; - - GET_LDOUBLE_WORDS (es, hx, lx, x); - - if (__glibc_unlikely (((es & 0x7fff) | hx | lx) == 0)) - { - /* Return value for x == 0 is Inf with divide by zero exception. */ - *signgamp = 0; - return 1.0 / x; - } - if (__glibc_unlikely (es == 0xffffffff && ((hx & 0x7fffffff) | lx) == 0)) - { - /* x == -Inf. According to ISO this is NaN. */ - *signgamp = 0; - return x - x; - } - if (__glibc_unlikely ((es & 0x7fff) == 0x7fff)) - { - /* Positive infinity (return positive infinity) or NaN (return - NaN). */ - *signgamp = 0; - return x + x; - } - if (__builtin_expect ((es & 0x8000) != 0, 0) && __rintl (x) == x) - { - /* Return value for integer x < 0 is NaN with invalid exception. */ - *signgamp = 0; - return (x - x) / (x - x); - } - - if (x >= 1756.0L) - { - /* Overflow. */ - *signgamp = 0; - return LDBL_MAX * LDBL_MAX; - } - else - { - SET_RESTORE_ROUNDL (FE_TONEAREST); - if (x > 0.0L) - { - *signgamp = 0; - int exp2_adj; - ret = gammal_positive (x, &exp2_adj); - ret = __scalbnl (ret, exp2_adj); - } - else if (x >= -LDBL_EPSILON / 4.0L) - { - *signgamp = 0; - ret = 1.0L / x; - } - else - { - long double tx = __truncl (x); - *signgamp = (tx == 2.0L * __truncl (tx / 2.0L)) ? -1 : 1; - if (x <= -1766.0L) - /* Underflow. */ - ret = LDBL_MIN * LDBL_MIN; - else - { - long double frac = tx - x; - if (frac > 0.5L) - frac = 1.0L - frac; - long double sinpix = (frac <= 0.25L - ? __sinl (M_PIl * frac) - : __cosl (M_PIl * (0.5L - frac))); - int exp2_adj; - ret = M_PIl / (-x * sinpix - * gammal_positive (-x, &exp2_adj)); - ret = __scalbnl (ret, -exp2_adj); - math_check_force_underflow_nonneg (ret); - } - } - } - if (isinf (ret) && x != 0) - { - if (*signgamp < 0) - return -(-__copysignl (LDBL_MAX, ret) * LDBL_MAX); - else - return __copysignl (LDBL_MAX, ret) * LDBL_MAX; - } - else if (ret == 0) - { - if (*signgamp < 0) - return -(-__copysignl (LDBL_MIN, ret) * LDBL_MIN); - else - return __copysignl (LDBL_MIN, ret) * LDBL_MIN; - } - else - return ret; -} -strong_alias (__ieee754_gammal_r, __gammal_r_finite) |