| /* k_cosf.c -- float version of k_cos.c |
| Copyright (C) 2011-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Adhemerval Zanella <azanella@br.ibm.com>, 2011 |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public License as |
| published by the Free Software Foundation; either version 2 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 |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with the GNU C Library; see the file COPYING.LIB. If |
| not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include <math.h> |
| #include <fenv.h> |
| #include <math_private.h> |
| |
| static const float twom27 = 7.4505806e-09; |
| static const float dot3 = 3.0000001e-01; |
| static const float dot78125 = 7.8125000e-01; |
| |
| static const float one = 1.0000000000e+00; |
| static const float C1 = 4.1666667908e-02; |
| static const float C2 = -1.3888889225e-03; |
| static const float C3 = 2.4801587642e-05; |
| static const float C4 = -2.7557314297e-07; |
| static const float C5 = 2.0875723372e-09; |
| static const float C6 = -1.1359647598e-11; |
| |
| float |
| __kernel_cosf (float x, float y) |
| { |
| float a, hz, z, r, qx; |
| float ix; |
| ix = __builtin_fabsf (x); |
| if (ix < twom27) |
| { /* |x| < 2**-27 */ |
| __feraiseexcept (FE_INEXACT); |
| return one; |
| } |
| z = x * x; |
| r = z * (C1 + z * (C2 + z * (C3 + z * (C4 + z * (C5 + z * C6))))); |
| if (ix < dot3) /* if |x| < 0.3 */ |
| return one - ((float) 0.5 * z - (z * r - x * y)); |
| else |
| { |
| if (ix > dot78125) |
| { /* x > 0.78125 */ |
| qx = (float) 0.28125; |
| } |
| else |
| { |
| qx = ix / 4.0; |
| } |
| hz = (float) 0.5 *z - qx; |
| a = one - qx; |
| return a - (hz - (z * r - x * y)); |
| } |
| } |