| /* mpfr_modf -- Integral and fractional part. |
| |
| Copyright 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" |
| |
| /* Set iop to the integral part of op and fop to its fractional part */ |
| int |
| mpfr_modf (mpfr_ptr iop, mpfr_ptr fop, mpfr_srcptr op, mpfr_rnd_t rnd_mode) |
| { |
| mp_exp_t ope; |
| mp_prec_t opq; |
| int inexact; |
| MPFR_SAVE_EXPO_DECL (expo); |
| |
| MPFR_LOG_FUNC (("op[%#R]=%R rnd=%d", op, op, rnd_mode), |
| ("iop[%#R]=%R fop[%#R]=%R", iop, iop, fop, fop)); |
| |
| MPFR_ASSERTN (iop != fop); |
| |
| if ( MPFR_UNLIKELY (MPFR_IS_SINGULAR (op)) ) |
| { |
| if (MPFR_IS_NAN (op)) |
| { |
| MPFR_SET_NAN (iop); |
| MPFR_SET_NAN (fop); |
| MPFR_RET_NAN; |
| } |
| MPFR_SET_SAME_SIGN (iop, op); |
| MPFR_SET_SAME_SIGN (fop, op); |
| if (MPFR_IS_INF (op)) |
| { |
| MPFR_SET_INF (iop); |
| MPFR_SET_ZERO (fop); |
| MPFR_RET (0); |
| } |
| else /* op is zero */ |
| { |
| MPFR_ASSERTD (MPFR_IS_ZERO (op)); |
| MPFR_SET_ZERO (iop); |
| MPFR_SET_ZERO (fop); |
| MPFR_RET (0); |
| } |
| } |
| |
| MPFR_SAVE_EXPO_MARK (expo); |
| |
| ope = MPFR_GET_EXP (op); |
| opq = MPFR_PREC (op); |
| |
| if (ope <=0) /* 0 < |op| < 1 */ |
| { |
| inexact = (fop != op) ? mpfr_set (fop, op, rnd_mode) : 0; |
| MPFR_SET_SAME_SIGN (iop, op); |
| MPFR_SET_ZERO (iop); |
| MPFR_SAVE_EXPO_FREE (expo); |
| mpfr_check_range (fop, inexact, rnd_mode); /* set the underflow flag if needed */ |
| MPFR_RET (MPFR_INT_SIGN (op) > 0 ? -2 : +2); |
| } |
| else if (ope >= opq) /* op has no fractional part */ |
| { |
| inexact = (iop != op)? mpfr_set (iop, op, rnd_mode) : 0; |
| MPFR_SET_SAME_SIGN (fop, op); |
| MPFR_SET_ZERO (fop); |
| MPFR_SAVE_EXPO_FREE (expo); |
| return mpfr_check_range (iop, inexact, rnd_mode); /* set the overflow flag if needed */ |
| } |
| else /* op has both integral and fractional parts */ |
| { |
| int inexi, inexf; |
| mpfr_t opf, opi; |
| |
| /* opi and opf are set with minimal but sufficient precision */ |
| mpfr_init2 (opi, ope <= MPFR_PREC_MIN ? MPFR_PREC_MIN : ope); |
| inexi = mpfr_trunc (opi, op); |
| mpfr_init2 (opf, opq - ope <= MPFR_PREC_MIN ? MPFR_PREC_MIN : opq - ope); |
| inexf = mpfr_frac (opf, op, GMP_RNDZ); |
| MPFR_ASSERTD (inexf == 0); |
| |
| inexf = mpfr_set (fop, opf, rnd_mode); |
| inexi = mpfr_set (iop, opi, rnd_mode); |
| mpfr_clear (opi); |
| mpfr_clear (opf); |
| |
| MPFR_SAVE_EXPO_FREE (expo); |
| inexf = mpfr_check_range (fop, inexf, rnd_mode); |
| inexi = mpfr_check_range (iop, inexi, rnd_mode); |
| |
| /* return value like mpfr_trunc(): */ |
| /* 0 iff iop and fop are exact */ |
| /* -1 if op is an integer, op > iop */ |
| /* +1 if op is an integer, op < iop */ |
| /* -2 if op is not an integer, op > 0 */ |
| /* +2 if op is not an integer, op < 0 */ |
| inexact = inexf ? (inexi ? 2 * inexi : -2 * MPFR_INT_SIGN (op)) : |
| (mpfr_zero_p (fop) ? inexi : 2 * inexi); |
| MPFR_RET (inexact); |
| } |
| } |