third-party-mirror / mingw-w64 / 9b207d4da4806fdaea3bf9f4a5d66dc6056670b6 / . / mingw-w64-crt / math / softmath / cos.c

/* | |

This Software is provided under the Zope Public License (ZPL) Version 2.1. | |

Copyright (c) 2014 by the mingw-w64 project | |

See the AUTHORS file for the list of contributors to the mingw-w64 project. | |

This license has been certified as open source. It has also been designated | |

as GPL compatible by the Free Software Foundation (FSF). | |

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in the documentation and/or other materials provided with the | |

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the copyright holders. Use of them is covered by separate agreement | |

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5. If any files are modified, you must cause the modified files to carry | |

prominent notices stating that you changed the files and the date of | |

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Disclaimer | |

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY EXPRESSED | |

OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |

OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO | |

EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT, | |

INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |

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*/ | |

#include "softmath_private.h" | |

double cos(double x) | |

{ | |

double result = 0.0, neg = (x < 0) ? -1 : 1; | |

int n, quadrant; | |

int x_class = fpclassify(x); | |

if (x_class == FP_NAN) | |

{ | |

errno = EDOM; | |

__mingw_raise_matherr (_DOMAIN, "cos", x, 0.0, x); | |

return x; | |

} | |

else if (x_class == FP_INFINITE) | |

{ | |

errno = EDOM; | |

__mingw_raise_matherr (_DOMAIN, "cos", x, 0.0, NAN); | |

return NAN; | |

} | |

x *= neg; | |

quadrant = (int)(x / M_PI_2) % 4; | |

x = bsd__ieee754_fmod(x, M_PI_2); | |

if (quadrant == 1 || quadrant == 3) | |

x = M_PI_2 - x; | |

for(n = 0; n < 6; n++) | |

{ | |

double sign = (n % 2 == 0) ? 1 : -1; | |

result += sign * (bsd__ieee754_pow(x, (2 * n)) / softmath_fact(2 * n)); | |

} | |

if (quadrant == 1 || quadrant == 2) | |

result *= -1; | |

return result; | |

} |