efee5258bc
The MPFR library is a C library for multiple-precision floating-point computations with exact rounding (also called correct rounding). It is based on the GMP multiple-precision library and should replace the MPF class in further releases of GMP. GCC >= 4.2 requires MPFR.
97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/* mpfr_ui_div -- divide a machine integer by a floating-point number
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mpfr_si_div -- divide a machine number by a floating-point number
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Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
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Contributed by the Arenaire and Cacao projects, INRIA.
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This file is part of the GNU MPFR Library.
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The GNU MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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The GNU MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
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http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
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#define MPFR_NEED_LONGLONG_H
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#include "mpfr-impl.h"
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int
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mpfr_ui_div (mpfr_ptr y, unsigned long int u, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
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{
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mpfr_t uu;
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mp_limb_t up[1];
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unsigned long cnt;
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if (MPFR_UNLIKELY(MPFR_IS_SINGULAR(x)))
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{
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if (MPFR_IS_NAN(x))
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{
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MPFR_SET_NAN(y);
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MPFR_RET_NAN;
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}
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else if (MPFR_IS_INF(x)) /* u/Inf = 0 */
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{
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MPFR_SET_ZERO(y);
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MPFR_SET_SAME_SIGN(y,x);
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MPFR_RET(0);
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}
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else /* u / 0 */
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{
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MPFR_ASSERTD(MPFR_IS_ZERO(x));
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if (u)
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{
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/* u > 0, so y = sign(x) * Inf */
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MPFR_SET_SAME_SIGN(y, x);
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MPFR_SET_INF(y);
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MPFR_RET(0);
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}
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else
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{
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/* 0 / 0 */
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MPFR_SET_NAN(y);
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MPFR_RET_NAN;
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}
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}
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}
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else if (MPFR_LIKELY(u != 0))
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{
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MPFR_TMP_INIT1(up, uu, GMP_NUMB_BITS);
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MPFR_ASSERTN(u == (mp_limb_t) u);
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count_leading_zeros(cnt, (mp_limb_t) u);
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up[0] = (mp_limb_t) u << cnt;
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MPFR_SET_EXP (uu, GMP_NUMB_BITS - cnt);
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return mpfr_div (y, uu, x, rnd_mode);
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}
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else /* u = 0, and x != 0 */
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{
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MPFR_SET_ZERO(y); /* if u=0, then set y to 0 */
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MPFR_SET_SAME_SIGN(y, x); /* u considered as +0: sign(+0/x) = sign(x) */
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MPFR_RET(0);
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}
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}
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int mpfr_si_div (mpfr_ptr y, long int u, mpfr_srcptr x,mpfr_rnd_t rnd_mode)
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{
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int res;
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if (u >= 0)
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res = mpfr_ui_div (y, u, x, rnd_mode);
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else
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{
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res = -mpfr_ui_div (y, -u, x, MPFR_INVERT_RND(rnd_mode));
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MPFR_CHANGE_SIGN (y);
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}
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return res;
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}
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