--- /dev/null
+/* 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);
+ }
+}