source/libs/gmp/gmp-src/mpf/div_ui.c

   1 /* mpf_div_ui -- Divide a float with an unsigned integer.
   2
   3 Copyright 1993, 1994, 1996, 2000-2002, 2004, 2005, 2012 Free Software
   4 Foundation, Inc.
   5
   6 This file is part of the GNU MP Library.
   7
   8 The GNU MP Library is free software; you can redistribute it and/or modify
   9 it under the terms of either:
  10
  11   * the GNU Lesser General Public License as published by the Free
  12     Software Foundation; either version 3 of the License, or (at your
  13     option) any later version.
  14
  15 or
  16
  17   * the GNU General Public License as published by the Free Software
  18     Foundation; either version 2 of the License, or (at your option) any
  19     later version.
  20
  21 or both in parallel, as here.
  22
  23 The GNU MP Library is distributed in the hope that it will be useful, but
  24 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  25 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  26 for more details.
  27
  28 You should have received copies of the GNU General Public License and the
  29 GNU Lesser General Public License along with the GNU MP Library.  If not,
  30 see https://www.gnu.org/licenses/.  */
  31
  32 #include "gmp.h"
  33 #include "gmp-impl.h"
  34 #include "longlong.h"
  35
  36 void
  37 mpf_div_ui (mpf_ptr r, mpf_srcptr u, unsigned long int v)
  38 {
  39   mp_srcptr up;
  40   mp_ptr rp, tp, rtp;
  41   mp_size_t usize;
  42   mp_size_t rsize, tsize;
  43   mp_size_t sign_quotient;
  44   mp_size_t prec;
  45   mp_limb_t q_limb;
  46   mp_exp_t rexp;
  47   TMP_DECL;
  48
  49 #if BITS_PER_ULONG > GMP_NUMB_BITS  /* avoid warnings about shift amount */
  50   if (v > GMP_NUMB_MAX)
  51     {
  52       mpf_t vf;
  53       mp_limb_t vl[2];
  54       SIZ(vf) = 2;
  55       EXP(vf) = 2;
  56       PTR(vf) = vl;
  57       vl[0] = v & GMP_NUMB_MASK;
  58       vl[1] = v >> GMP_NUMB_BITS;
  59       mpf_div (r, u, vf);
  60       return;
  61     }
  62 #endif
  63
  64   if (UNLIKELY (v == 0))
  65     DIVIDE_BY_ZERO;
  66
  67   usize = u->_mp_size;
  68
  69   if (usize == 0)
  70     {
  71       r->_mp_size = 0;
  72       r->_mp_exp = 0;
  73       return;
  74     }
  75
  76   sign_quotient = usize;
  77   usize = ABS (usize);
  78   prec = r->_mp_prec;
  79
  80   TMP_MARK;
  81
  82   rp = r->_mp_d;
  83   up = u->_mp_d;
  84
  85   tsize = 1 + prec;
  86   tp = TMP_ALLOC_LIMBS (tsize + 1);
  87
  88   if (usize > tsize)
  89     {
  90       up += usize - tsize;
  91       usize = tsize;
  92       rtp = tp;
  93     }
  94   else
  95     {
  96       MPN_ZERO (tp, tsize - usize);
  97       rtp = tp + (tsize - usize);
  98     }
  99
 100   /* Move the dividend to the remainder.  */
 101   MPN_COPY (rtp, up, usize);
 102
 103   mpn_divmod_1 (rp, tp, tsize, (mp_limb_t) v);
 104   q_limb = rp[tsize - 1];
 105
 106   rsize = tsize - (q_limb == 0);
 107   rexp = u->_mp_exp - (q_limb == 0);
 108   r->_mp_size = sign_quotient >= 0 ? rsize : -rsize;
 109   r->_mp_exp = rexp;
 110   TMP_FREE;
 111 }