sysdeps/powerpc/fpu/s_sinf.c

   1 /* s_sinf.c -- float version of s_sin.c.
   2    Copyright (C) 2011-2015 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Adhemerval Zanella <azanella@br.ibm.com>, 2011
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    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    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If
  18    not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include <errno.h>
  21 #include <math.h>
  22 #include <math_private.h>
  23
  24 static const float pio4 = 7.8539801e-1;
  25
  26 float
  27 __sinf (float x)
  28 {
  29   float y[2], z = 0.0;
  30   float ix;
  31   int32_t n;
  32
  33   ix = __builtin_fabsf (x);
  34
  35   /* |x| ~< pi/4 */
  36   if (ix <= pio4)
  37     {
  38       return __kernel_sinf (x, z, 0);
  39       /* sin(Inf or NaN) is NaN */
  40     }
  41   else if (isnanf (ix))
  42     {
  43       return x - x;
  44     }
  45   else if (isinff (ix))
  46     {
  47       __set_errno (EDOM);
  48       return x - x;
  49     }
  50
  51   /* argument reduction needed */
  52   else
  53     {
  54       n = __ieee754_rem_pio2f (x, y);
  55       switch (n & 3)
  56         {
  57         case 0:
  58           return __kernel_sinf (y[0], y[1], 1);
  59         case 1:
  60           return __kernel_cosf (y[0], y[1]);
  61         case 2:
  62           return -__kernel_sinf (y[0], y[1], 1);
  63         default:
  64           return -__kernel_cosf (y[0], y[1]);
  65         }
  66     }
  67 }
  68
  69 weak_alias (__sinf, sinf)