sysdeps/ieee754/flt-32/s_sincosf.c

   1 /* Compute sine and cosine of argument.
   2    Copyright (C) 1997-2014 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <math.h>
  21
  22 #include <math_private.h>
  23
  24 #ifndef SINCOSF
  25 # define SINCOSF_FUNC __sincosf
  26 #else
  27 # define SINCOSF_FUNC SINCOSF
  28 #endif
  29
  30 void
  31 SINCOSF_FUNC (float x, float *sinx, float *cosx)
  32 {
  33   int32_t ix;
  34
  35   /* High word of x. */
  36   GET_FLOAT_WORD (ix, x);
  37
  38   /* |x| ~< pi/4 */
  39   ix &= 0x7fffffff;
  40   if (ix <= 0x3f490fd8)
  41     {
  42       *sinx = __kernel_sinf (x, 0.0, 0);
  43       *cosx = __kernel_cosf (x, 0.0);
  44     }
  45   else if (ix>=0x7f800000)
  46     {
  47       /* sin(Inf or NaN) is NaN */
  48       *sinx = *cosx = x - x;
  49     }
  50   else
  51     {
  52       /* Argument reduction needed.  */
  53       float y[2];
  54       int n;
  55
  56       n = __ieee754_rem_pio2f (x, y);
  57       switch (n & 3)
  58         {
  59         case 0:
  60           *sinx = __kernel_sinf (y[0], y[1], 1);
  61           *cosx = __kernel_cosf (y[0], y[1]);
  62           break;
  63         case 1:
  64           *sinx = __kernel_cosf (y[0], y[1]);
  65           *cosx = -__kernel_sinf (y[0], y[1], 1);
  66           break;
  67         case 2:
  68           *sinx = -__kernel_sinf (y[0], y[1], 1);
  69           *cosx = -__kernel_cosf (y[0], y[1]);
  70           break;
  71         default:
  72           *sinx = -__kernel_cosf (y[0], y[1]);
  73           *cosx = __kernel_sinf (y[0], y[1], 1);
  74           break;
  75         }
  76     }
  77 }
  78
  79 #ifndef SINCOSF
  80 weak_alias (__sincosf, sincosf)
  81 #endif