1  /* mpz_set_d(integer, val) -- Assign INTEGER with a double value VAL.
       2  
       3  Copyright 1995, 1996, 2000-2003, 2006, 2015 Free Software Foundation, Inc.
       4  
       5  This file is part of the GNU MP Library.
       6  
       7  The GNU MP Library is free software; you can redistribute it and/or modify
       8  it under the terms of either:
       9  
      10    * the GNU Lesser General Public License as published by the Free
      11      Software Foundation; either version 3 of the License, or (at your
      12      option) any later version.
      13  
      14  or
      15  
      16    * the GNU General Public License as published by the Free Software
      17      Foundation; either version 2 of the License, or (at your option) any
      18      later version.
      19  
      20  or both in parallel, as here.
      21  
      22  The GNU MP Library is distributed in the hope that it will be useful, but
      23  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      24  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      25  for more details.
      26  
      27  You should have received copies of the GNU General Public License and the
      28  GNU Lesser General Public License along with the GNU MP Library.  If not,
      29  see https://www.gnu.org/licenses/.  */
      30  
      31  #include "config.h"
      32  
      33  #if HAVE_FLOAT_H
      34  #include <float.h>  /* for DBL_MAX */
      35  #endif
      36  
      37  #include "gmp-impl.h"
      38  
      39  
      40  /* We used to have a special case for d < MP_BASE_AS_DOUBLE, just casting
      41     double -> limb.  Unfortunately gcc 3.3 on powerpc970-apple-darwin6.8.5
      42     got this wrong.  (It assumed __fixunsdfdi returned its result in a single
      43     64-bit register, where instead that function followed the calling
      44     conventions and gave the result in two parts r3 and r4.)  Hence the use
      45     of __gmp_extract_double in all cases.  */
      46  
      47  void
      48  mpz_set_d (mpz_ptr r, double d)
      49  {
      50    int negative;
      51    mp_limb_t tp[LIMBS_PER_DOUBLE];
      52    mp_ptr rp;
      53    mp_size_t rn;
      54  
      55    DOUBLE_NAN_INF_ACTION (d,
      56  			 __gmp_invalid_operation (),
      57  			 __gmp_invalid_operation ());
      58  
      59    negative = d < 0;
      60    d = ABS (d);
      61  
      62    rn = __gmp_extract_double (tp, d);
      63  
      64    if (rn <= 0)
      65      rn = 0;
      66  
      67    rp = MPZ_NEWALLOC (r, rn);
      68  
      69    switch (rn)
      70      {
      71      default:
      72        MPN_ZERO (rp, rn - LIMBS_PER_DOUBLE);
      73        rp += rn - LIMBS_PER_DOUBLE;
      74        /* fall through */
      75  #if LIMBS_PER_DOUBLE == 2
      76      case 2:
      77        rp[1] = tp[1], rp[0] = tp[0];
      78        break;
      79      case 1:
      80        rp[0] = tp[1];
      81        break;
      82  #endif
      83  #if LIMBS_PER_DOUBLE == 3
      84      case 3:
      85        rp[2] = tp[2], rp[1] = tp[1], rp[0] = tp[0];
      86        break;
      87      case 2:
      88        rp[1] = tp[2], rp[0] = tp[1];
      89        break;
      90      case 1:
      91        rp[0] = tp[2];
      92        break;
      93  #endif
      94  #if LIMBS_PER_DOUBLE == 4
      95      case 4:
      96        rp[3] = tp[3], rp[2] = tp[2], rp[1] = tp[1], rp[0] = tp[0];
      97        break;
      98      case 3:
      99        rp[2] = tp[3], rp[1] = tp[2], rp[0] = tp[1];
     100        break;
     101      case 2:
     102        rp[1] = tp[3], rp[0] = tp[2];
     103        break;
     104      case 1:
     105        rp[0] = tp[3];
     106        break;
     107  #endif
     108      case 0:
     109        break;
     110      }
     111  
     112    SIZ(r) = negative ? -rn : rn;
     113  }