Annotation of OpenXM_contrib/gmp/mpfr/ui_sub.c, Revision 1.1
1.1 ! ohara 1: /* mpfr_ui_sub -- subtract a floating-point number from an integer
! 2:
! 3: Copyright 2000, 2001, 2002 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 "longlong.h"
! 25: #include "mpfr.h"
! 26: #include "mpfr-impl.h"
! 27:
! 28: int
! 29: mpfr_ui_sub (mpfr_ptr y, unsigned long int u, mpfr_srcptr x, mp_rnd_t rnd_mode)
! 30: {
! 31: mpfr_t uu;
! 32: mp_limb_t up[1];
! 33: unsigned long cnt;
! 34:
! 35: if (MPFR_IS_NAN(x))
! 36: {
! 37: MPFR_SET_NAN(y);
! 38: MPFR_RET_NAN;
! 39: }
! 40:
! 41: MPFR_CLEAR_NAN(y);
! 42:
! 43: if (MPFR_IS_INF(x))
! 44: {
! 45: MPFR_SET_INF(y);
! 46: if (MPFR_SIGN(x) == MPFR_SIGN(y))
! 47: MPFR_CHANGE_SIGN(y);
! 48: MPFR_RET(0); /* +/-infinity is exact */
! 49: }
! 50:
! 51: if (u) {
! 52: MPFR_INIT1 (up, uu, BITS_PER_MP_LIMB, 1);
! 53: count_leading_zeros (cnt, (mp_limb_t) u);
! 54: *up = (mp_limb_t) u << cnt;
! 55: MPFR_EXP(uu) = BITS_PER_MP_LIMB - cnt;
! 56:
! 57: return mpfr_sub (y, uu, x, rnd_mode);
! 58: }
! 59: else
! 60: return mpfr_neg (y, x, rnd_mode); /* if u=0, then set y to -x */
! 61: }
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