third-party-mirror / GRTEv4 / cf41cedf52c87cf4f27c61e4eb8444ecb811ab13 / . / google3 / third_party / grte / v4_src / glibc-2.19 / math / e_exp2l.c

/* Compute 2^x. | |

Copyright (C) 2012-2014 Free Software Foundation, Inc. | |

This file is part of the GNU C Library. | |

The GNU C Library is free software; you can redistribute it and/or | |

modify it under the terms of the GNU Lesser General Public | |

License as published by the Free Software Foundation; either | |

version 2.1 of the License, or (at your option) any later version. | |

The GNU C Library is distributed in the hope that it will be useful, | |

but WITHOUT ANY WARRANTY; without even the implied warranty of | |

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |

Lesser General Public License for more details. | |

You should have received a copy of the GNU Lesser General Public | |

License along with the GNU C Library; if not, see | |

<http://www.gnu.org/licenses/>. */ | |

#include <math.h> | |

#include <math_private.h> | |

#include <float.h> | |

long double | |

__ieee754_exp2l (long double x) | |

{ | |

if (__builtin_expect (isless (x, (long double) LDBL_MAX_EXP), 1)) | |

{ | |

if (__builtin_expect (isgreaterequal (x, (long double) (LDBL_MIN_EXP | |

- LDBL_MANT_DIG | |

- 1)), 1)) | |

{ | |

int intx = (int) x; | |

long double fractx = x - intx; | |

return __scalbnl (__ieee754_expl (M_LN2l * fractx), intx); | |

} | |

else | |

{ | |

/* Underflow or exact zero. */ | |

if (__isinfl (x)) | |

return 0; | |

else | |

return LDBL_MIN * LDBL_MIN; | |

} | |

} | |

else | |

/* Infinity, NaN or overflow. */ | |

return LDBL_MAX * x; | |

} | |

strong_alias (__ieee754_exp2l, __exp2l_finite) |