Annotation of OpenXM_contrib/gmp/mpfr/div_2si.c, Revision 1.1
1.1 ! ohara 1: /* mpfr_div_2si -- divide a floating-point number by a power of two
! 2:
! 3: Copyright 1999, 2001 Free Software Foundation, Inc.
! 4:
! 5: This file is part of the MPFR Library.
! 6:
! 7: The MPFR Library is free software; you can redistribute it and/or modify
! 8: it under the terms of the GNU Lesser General Public License as published by
! 9: the Free Software Foundation; either version 2.1 of the License, or (at your
! 10: option) any later version.
! 11:
! 12: The MPFR Library is distributed in the hope that it will be useful, but
! 13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! 14: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
! 15: License for more details.
! 16:
! 17: You should have received a copy of the GNU Lesser General Public License
! 18: along with the MPFR Library; see the file COPYING.LIB. If not, write to
! 19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
! 20: MA 02111-1307, USA. */
! 21:
! 22: #include "gmp.h"
! 23: #include "gmp-impl.h"
! 24: #include "mpfr.h"
! 25: #include "mpfr-impl.h"
! 26:
! 27: int
! 28: mpfr_div_2si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
! 29: {
! 30: int inexact;
! 31:
! 32: inexact = y != x ? mpfr_set (y, x, rnd_mode) : 0;
! 33:
! 34: if (MPFR_IS_FP(y) && MPFR_NOTZERO(y))
! 35: {
! 36: if (n > 0 && (__mpfr_emin > MPFR_EMAX_MAX - n ||
! 37: MPFR_EXP(y) < __mpfr_emin + n))
! 38: return mpfr_set_underflow (y, rnd_mode, MPFR_SIGN(y));
! 39:
! 40: if (n < 0 && (__mpfr_emax < MPFR_EMIN_MIN - n ||
! 41: MPFR_EXP(y) > __mpfr_emax + n))
! 42: return mpfr_set_overflow (y, rnd_mode, MPFR_SIGN(y));
! 43:
! 44: MPFR_EXP(y) -= n;
! 45: }
! 46:
! 47: return inexact;
! 48: }
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