chromium / native_client / nacl-gcc / f80d6b9ee7f94755c697ffb7194fb01dd0c537dd / . / mpfr-2.4.1 / get_ui.c

/* mpfr_get_ui -- convert a floating-point number to an unsigned long. | |

Copyright 2003, 2004, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. | |

Contributed by the Arenaire and Cacao projects, INRIA. | |

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

The GNU MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LIB. If not, write to | |

the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, | |

MA 02110-1301, USA. */ | |

#include "mpfr-impl.h" | |

unsigned long | |

mpfr_get_ui (mpfr_srcptr f, mp_rnd_t rnd) | |

{ | |

mp_prec_t prec; | |

unsigned long s; | |

mpfr_t x; | |

mp_size_t n; | |

mp_exp_t exp; | |

if (!mpfr_fits_ulong_p (f, rnd)) | |

{ | |

MPFR_SET_ERANGE (); | |

return MPFR_IS_NEG (f) ? 0 : ULONG_MAX; | |

} | |

if (MPFR_IS_ZERO (f)) | |

return (unsigned long) 0; | |

for (s = ULONG_MAX, prec = 0; s != 0; s >>= 1, prec ++); | |

/* first round to prec bits */ | |

mpfr_init2 (x, prec); | |

mpfr_rint (x, f, rnd); | |

/* warning: if x=0, taking its exponent is illegal */ | |

if (MPFR_IS_ZERO(x)) | |

s = 0; | |

else | |

{ | |

/* now the result is in the most significant limb of x */ | |

exp = MPFR_GET_EXP (x); /* since |x| >= 1, exp >= 1 */ | |

n = MPFR_LIMB_SIZE(x); | |

s = MPFR_MANT(x)[n - 1] >> (BITS_PER_MP_LIMB - exp); | |

} | |

mpfr_clear (x); | |

return s; | |

} |