libquadmath/math/sincosq.c

   1 /* Compute sine and cosine of argument.
   2    Copyright (C) 1997-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
   5                   Jakub Jelinek <jj@ultra.linux.cz>.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #include "quadmath-imp.h"
  22
  23 void
  24 sincosq (__float128 x, __float128 *sinx, __float128 *cosx)
  25 {
  26   int64_t ix;
  27
  28   /* High word of x. */
  29   GET_FLT128_MSW64 (ix, x);
  30
  31   /* |x| ~< pi/4 */
  32   ix &= 0x7fffffffffffffffLL;
  33   if (ix <= 0x3ffe921fb54442d1LL)
  34     __quadmath_kernel_sincosq (x, 0, sinx, cosx, 0);
  35   else if (ix >= 0x7fff000000000000LL)
  36     {
  37       /* sin(Inf or NaN) is NaN */
  38       *sinx = *cosx = x - x;
  39       if (isinfq (x))
  40         errno = EDOM;
  41     }
  42   else
  43     {
  44       /* Argument reduction needed.  */
  45       __float128 y[2];
  46       int n;
  47
  48       n = __quadmath_rem_pio2q (x, y);
  49       switch (n & 3)
  50         {
  51         case 0:
  52           __quadmath_kernel_sincosq (y[0], y[1], sinx, cosx, 1);
  53           break;
  54         case 1:
  55           __quadmath_kernel_sincosq (y[0], y[1], cosx, sinx, 1);
  56           *cosx = -*cosx;
  57           break;
  58         case 2:
  59           __quadmath_kernel_sincosq (y[0], y[1], sinx, cosx, 1);
  60           *sinx = -*sinx;
  61           *cosx = -*cosx;
  62           break;
  63         default:
  64           __quadmath_kernel_sincosq (y[0], y[1], cosx, sinx, 1);
  65           *sinx = -*sinx;
  66           break;
  67         }
  68     }
  69 }