120 lines
3.1 KiB
C
120 lines
3.1 KiB
C
/* mpf_ui_div -- Divide an unsigned integer with a float.
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Copyright 1993, 1994, 1995, 1996, 2000, 2001, 2002, 2004, 2005 Free Software
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Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP 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 2.1 of the License, or (at your
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option) any later version.
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The GNU MP 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 MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include <stdio.h> /* for NULL */
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#include "mpir.h"
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#include "gmp-impl.h"
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#include "longlong.h"
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void
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mpf_ui_div (mpf_ptr r, mpir_ui u, mpf_srcptr v)
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{
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mp_srcptr vp;
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mp_ptr rp, tp, remp, new_vp;
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mp_size_t vsize;
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mp_size_t rsize, prospective_rsize, zeros, tsize, high_zero;
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mp_size_t sign_quotient;
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mp_size_t prec;
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mp_exp_t rexp;
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TMP_DECL;
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vsize = v->_mp_size;
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sign_quotient = vsize;
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vsize = ABS (vsize);
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prec = r->_mp_prec;
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if (UNLIKELY (vsize == 0))
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DIVIDE_BY_ZERO;
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if (UNLIKELY (u == 0))
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{
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r->_mp_size = 0;
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r->_mp_exp = 0;
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return;
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}
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TMP_MARK;
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rexp = 1 - v->_mp_exp + 1;
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rp = r->_mp_d;
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vp = v->_mp_d;
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prospective_rsize = 1 - vsize + 1; /* quot from using given u,v sizes */
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rsize = prec + 1; /* desired quot size */
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zeros = rsize - prospective_rsize; /* padding u to give rsize */
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tsize = 1 + zeros; /* u with zeros */
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if (WANT_TMP_DEBUG)
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{
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/* separate alloc blocks, for malloc debugging */
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remp = TMP_ALLOC_LIMBS (vsize);
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tp = TMP_ALLOC_LIMBS (tsize);
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new_vp = NULL;
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if (rp == vp)
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new_vp = TMP_ALLOC_LIMBS (vsize);
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}
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else
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{
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/* one alloc with calculated size, for efficiency */
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mp_size_t size = vsize + tsize + (rp == vp ? vsize : 0);
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remp = TMP_ALLOC_LIMBS (size);
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tp = remp + vsize;
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new_vp = tp + tsize;
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}
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/* ensure divisor doesn't overlap quotient */
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if (rp == vp)
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{
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MPN_COPY (new_vp, vp, vsize);
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vp = new_vp;
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}
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MPN_ZERO (tp, tsize-1);
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tp[tsize - 1] = u & GMP_NUMB_MASK;
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#if BITS_PER_UI > GMP_NUMB_BITS
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if (u > GMP_NUMB_MAX)
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{
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/* tsize-vsize+1 == rsize, so tsize >= rsize. rsize == prec+1 >= 2,
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so tsize >= 2, hence there's room for 2-limb u with nails */
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ASSERT (tsize >= 2);
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tp[tsize - 1] = u >> GMP_NUMB_BITS;
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tp[tsize - 2] = u & GMP_NUMB_MASK;
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rexp++;
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}
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#endif
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ASSERT (tsize-vsize+1 == rsize);
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mpn_tdiv_qr (rp, remp, (mp_size_t) 0, tp, tsize, vp, vsize);
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/* strip possible zero high limb */
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high_zero = (rp[rsize-1] == 0);
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rsize -= high_zero;
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rexp -= high_zero;
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r->_mp_size = sign_quotient >= 0 ? rsize : -rsize;
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r->_mp_exp = rexp;
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TMP_FREE;
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}
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