chromium / native_client / nacl-gcc / f80d6b9ee7f94755c697ffb7194fb01dd0c537dd / . / mpfr-2.4.1 / fits_s.h

/* mpfr_fits_*_p -- test whether an mpfr fits a C signed type. | |

Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. | |

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

Copied from mpf/fits_s.h. | |

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" | |

int | |

FUNCTION (mpfr_srcptr f, mp_rnd_t rnd) | |

{ | |

mp_exp_t exp; | |

mp_prec_t prec; | |

TYPE s; | |

mpfr_t x; | |

int neg; | |

int res; | |

if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (f))) | |

/* Zero always fit */ | |

return MPFR_IS_ZERO (f) ? 1 : 0; | |

/* now it fits if either | |

(a) MINIMUM <= f <= MAXIMUM | |

(b) or MINIMUM <= round(f, prec(slong), rnd) <= MAXIMUM */ | |

exp = MPFR_GET_EXP (f); | |

if (exp < 1) | |

return 1; /* |f| < 1: always fits */ | |

neg = MPFR_IS_NEG (f); | |

/* let EXTREMUM be MAXIMUM if f > 0, and MINIMUM if f < 0 */ | |

/* first compute prec(EXTREMUM), this could be done at configure time */ | |

s = (neg) ? MINIMUM : MAXIMUM; | |

for (prec = 0; s != 0; s /= 2, prec ++); | |

/* EXTREMUM needs prec bits, i.e. 2^(prec-1) <= |EXTREMUM| < 2^prec */ | |

/* if exp < prec - 1, then f < 2^(prec-1) < |EXTREMUM| */ | |

if ((mpfr_prec_t) exp < prec - 1) | |

return 1; | |

/* if exp > prec + 1, then f >= 2^prec > EXTREMUM */ | |

if ((mpfr_prec_t) exp > prec + 1) | |

return 0; | |

/* remains cases exp = prec-1 to prec+1 */ | |

/* hard case: first round to prec bits, then check */ | |

mpfr_init2 (x, prec); | |

mpfr_set (x, f, rnd); | |

res = (neg) ? (mpfr_cmp_si (x, MINIMUM) >= 0) | |

: (mpfr_cmp_si (x, MAXIMUM) <= 0); | |

mpfr_clear (x); | |

return res; | |

} | |