libquadmath/math/sincosq.c

   1 /* Compute sine and cosine of argument.
   2    Copyright (C) 1997-2017 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, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #include <errno.h>
  23 #include "quadmath-imp.h"
  24
  25 void
  26 sincosq (__float128 x, __float128 *sinx, __float128 *cosx)
  27 {
  28   int64_t ix;
  29
  30   /* High word of x. */
  31   GET_FLT128_MSW64 (ix, x);
  32
  33   /* |x| ~< pi/4 */
  34   ix &= 0x7fffffffffffffffLL;
  35   if (ix <= 0x3ffe921fb54442d1LL)
  36     __quadmath_kernel_sincosq (x, 0.0Q, sinx, cosx, 0);
  37   else if (ix >= 0x7fff000000000000LL)
  38     {
  39       /* sin(Inf or NaN) is NaN */
  40       *sinx = *cosx = x - x;
  41       if (isinfq (x))
  42         errno = EDOM;
  43     }
  44   else
  45     {
  46       /* Argument reduction needed.  */
  47       __float128 y[2];
  48       int n;
  49
  50       n = __quadmath_rem_pio2q (x, y);
  51       switch (n & 3)
  52         {
  53         case 0:
  54           __quadmath_kernel_sincosq (y[0], y[1], sinx, cosx, 1);
  55           break;
  56         case 1:
  57           __quadmath_kernel_sincosq (y[0], y[1], cosx, sinx, 1);
  58           *cosx = -*cosx;
  59           break;
  60         case 2:
  61           __quadmath_kernel_sincosq (y[0], y[1], sinx, cosx, 1);
  62           *sinx = -*sinx;
  63           *cosx = -*cosx;
  64           break;
  65         default:
  66           __quadmath_kernel_sincosq (y[0], y[1], cosx, sinx, 1);
  67           *sinx = -*sinx;
  68           break;
  69         }
  70     }
  71 }